Genetically encoded biosensors for detection of polyketides
11486010 · 2022-11-01
Assignee
Inventors
Cpc classification
C12Q1/6897
CHEMISTRY; METALLURGY
International classification
Abstract
The present disclosure relates to high-throughput detection of polyketides using genetically encoded biosensors.
Claims
1. A biosensor system comprising: a nucleic acid encoding a genetically modified MphR gene sequence, wherein the nucleic acid comprises at least one genetic mutation comprising at least one nucleotide change in the ribosome binding site sequence when compared to a wild-type MphR gene sequence; and a reporter gene whose transcription is under the control of a promoter region which is regulated by a wild-type MphR transcription factor.
2. The biosensor system of claim 1, wherein the nucleic acid encoding the genetically modified MphR gene sequence and the reporter gene are located on one recombinant DNA vector.
3. The biosensor system of claim 1, wherein the reporter gene is a gene coding for chloramphenicol acetyltransferase, beta-galactosidase, luciferase or green fluorescent protein (GFP).
4. The biosensor system of claim 3, wherein the reporter gene is a gene coding for green fluorescent protein (GFP).
5. The biosensor system of claim 1, wherein the at least one nucleotide change in the ribosome binding site sequence is selected from A1G, A1T, A1C, G2T, G2A, A3C, A3G, A4T, G5T, G6T, or a combination thereof.
6. The biosensor system of claim 1, wherein the at least one nucleotide change in the ribosome binding site sequence is selected from A1G, A4T, or a combination thereof.
7. A genetically modified host cell comprising: a nucleic acid encoding the biosensor system of claim 1.
8. The cell of claim 7, wherein the at least one nucleotide change in the ribosome binding site sequence is selected from A1G, A1T, A1C, G2T, G2A, A3C, A3G, A4T, G5T, G6T, or a combination thereof.
9. The cell of claim 7, wherein the cell is E. coli.
10. The cell of claim 7, wherein the cell is Streptomyces.
11. A method for detecting a polyketide, comprising: introducing into a cell: a nucleic acid encoding a genetically modified MphR gene sequence, wherein the nucleic acid comprises at least one nucleotide change in the ribosome binding site sequence when compared to a wild-type MphR gene sequence; and a reporter gene whose transcription is under the control of a promoter region which is regulated by a wild-type MphR transcription factor; and detecting the presence or absence of the polyketide based on the differential expression of the reporter gene in comparison to a cell comprising the wild-type MphR gene sequence.
12. The method of claim 11, wherein the at least one nucleotide change in the ribosome binding site sequence is selected from A1G, A1T, A1C, G2T, G2A, A3C, A3G, A4T, G5T, G6T, or a combination thereof.
13. The method of claim 11, wherein the cell is E. coli.
14. The method of claim 11, wherein the cell is Streptomyces.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying figures, which are incorporated in and constitute a part of this specification, illustrate several aspects described below.
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DETAILED DESCRIPTION OF THE INVENTION
(35) Described herein is a platform technology that comprises genetically-encoded biosensors and methods for detection of polyketides using mutated MphR gene sequences. Such biosensors provide a scalable, economic, high-throughput, and broadly applicable means to specifically identify a target polyketide of interest from a complex mixture of molecules.
(36) Reference will now be made in detail to the embodiments of the invention, examples of which are illustrated in the drawings and the examples. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
(37) Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. The following definitions are provided for the full understanding of terms used in this specification.
Terminology
(38) Terms used throughout this application are to be construed with ordinary and typical meaning to those of ordinary skill in the art. However, Applicant desires that the following terms be given the particular definition as defined below.
(39) As used in the specification and claims, the singular form “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a cell” includes a plurality of cells, including mixtures thereof.
(40) As used herein, the terms “may,” “optionally,” and “may optionally” are used interchangeably and are meant to include cases in which the condition occurs as well as cases in which the condition does not occur.
(41) The terms “about” and “approximately” are defined as being “close to” as understood by one of ordinary skill in the art. In one non-limiting embodiment the terms are defined to be within 10%. In another non-limiting embodiment, the terms are defined to be within 5%. In still another non-limiting embodiment, the terms are defined to be within 1%.
(42) The term “nucleic acid” as used herein means a polymer composed of nucleotides, e.g. deoxyribonucleotides or ribonucleotides.
(43) The terms “ribonucleic acid” and “RNA” as used herein mean a polymer composed of ribonucleotides.
(44) The terms “deoxyribonucleic acid” and “DNA” as used herein mean a polymer composed of deoxyribonucleotides.
(45) The term “oligonucleotide” denotes single- or double-stranded nucleotide multimers of from about 2 to up to about 100 nucleotides in length. Suitable oligonucleotides may be prepared by the phosphoramidite method described by Beaucage and Carruthers, Tetrahedron Lett., 22:1859-1862 (1981), or by the triester method according to Matteucci, et al., J. Am. Chem. Soc., 103:3185 (1981), both incorporated herein by reference, or by other chemical methods using either a commercial automated oligonucleotide synthesizer or VLSIPS™ technology. When oligonucleotides are referred to as “double-stranded,” it is understood by those of skill in the art that a pair of oligonucleotides exist in a hydrogen-bonded, helical array typically associated with, for example, DNA. In addition to the 100% complementary form of double-stranded oligonucleotides, the term “double-stranded,” as used herein is also meant to refer to those forms which include such structural features as bulges and loops, described more fully in such biochemistry texts as Stryer, Biochemistry, Third Ed., (1988), incorporated herein by reference for all purposes.
(46) The term “polynucleotide” refers to a single or double stranded polymer composed of nucleotide monomers. In some embodiments, the polynucleotide is composed of nucleotide monomers of generally greater than 100 nucleotides in length and up to about 8,000 or more nucleotides in length.
(47) The term “polypeptide” refers to a compound made up of a single chain of D- or L-amino acids or a mixture of D- and L-amino acids joined by peptide bonds.
(48) The term “promoter” or “regulatory element” refers to a region or sequence determinants located upstream or downstream from the start of transcription and which are involved in recognition and binding of RNA polymerase and other proteins to initiate transcription. Promoters need not be of bacterial origin, for example, promoters derived from viruses or from other organisms can be used in the compositions, systems, or methods described herein
(49) The term “recombinant” refers to a human manipulated nucleic acid (e.g. polynucleotide) or a copy or complement of a human manipulated nucleic acid (e.g. polynucleotide), or if in reference to a protein (i.e, a “recombinant protein”), a protein encoded by a recombinant nucleic acid (e.g. polynucleotide). In embodiments, a recombinant expression cassette comprising a promoter operably linked to a second nucleic acid (e.g. polynucleotide) may include a promoter that is heterologous to the second nucleic acid (e.g. polynucleotide) as the result of human manipulation (e.g., by methods described in Sambrook et al., Molecular Cloning—A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y., (1989) or Current Protocols in Molecular Biology Volumes 1-3, John Wiley & Sons, Inc. (1994-1998)). In another example, a recombinant expression cassette may comprise nucleic acids (e.g. polynucleotides) combined in such a way that the nucleic acids (e.g. polynucleotides) are extremely unlikely to be found in nature. For instance, human manipulated restriction sites or plasmid vector sequences may flank or separate the promoter from the second nucleic acid (e.g. polynucleotide). One of skill will recognize that nucleic acids (e.g. polynucleotides) can be manipulated in many ways and are not limited to the examples above.
(50) The terms “identical” or percent “identity,” in the context of two or more nucleic acids or polypeptide sequences, refer to two or more sequences or subsequences that are the same or have a specified percentage of amino acid residues or nucleotides that are the same (i.e., about 60% identity, preferably 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher identity over a specified region when compared and aligned for maximum correspondence over a comparison window or designated region) as measured using a BLAST or BLAST 2.0 sequence comparison algorithms with default parameters described below, or by manual alignment and visual inspection (see, e.g., NCBI web site or the like). Such sequences are then said to be “substantially identical.” This definition also refers to, or may be applied to, the compliment of a test sequence. The definition also includes sequences that have deletions and/or additions, as well as those that have substitutions. As described below, the preferred algorithms can account for gaps and the like. Preferably, identity exists over a region that is at least about 10 amino acids or 20 nucleotides in length, or more preferably over a region that is 10-50 amino acids or 20-50 nucleotides in length. As used herein, percent (%) amino acid sequence identity is defined as the percentage of amino acids in a candidate sequence that are identical to the amino acids in a reference sequence, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity. Alignment for purposes of determining percent sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, BLAST-2, ALIGN, ALIGN-2 or Megalign (DNASTAR) software. Appropriate parameters for measuring alignment, including any algorithms needed to achieve maximal alignment over the full-length of the sequences being compared can be determined by known methods.
(51) For sequence comparisons, typically one sequence acts as a reference sequence, to which test sequences are compared. When using a sequence comparison algorithm, test and reference sequences are entered into a computer, subsequence coordinates are designated, if necessary, and sequence algorithm program parameters are designated. Preferably, default program parameters can be used, or alternative parameters can be designated. The sequence comparison algorithm then calculates the percent sequence identities for the test sequences relative to the reference sequence, based on the program parameters.
(52) One example of an algorithm that is suitable for determining percent sequence identity and sequence similarity are the BLAST and BLAST 2.0 algorithms, which are described in Altschul et al. (1977) Nuc. Acids Res. 25:3389-3402, and Altschul et al. (1990) J. Mol. Biol. 215:403-410, respectively. Software for performing BLAST analyses is publicly available through the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/). This algorithm involves first identifying high scoring sequence pairs (HSPs) by identifying short words of length W in the query sequence, which either match or satisfy some positive-valued threshold score T when aligned with a word of the same length in a database sequence. T is referred to as the neighborhood word score threshold (Altschul et al. (1990) J. Mol. Biol. 215:403-410). These initial neighborhood word hits act as seeds for initiating searches to find longer HSPs containing them. The word hits are extended in both directions along each sequence for as far as the cumulative alignment score can be increased. Cumulative scores are calculated using, for nucleotide sequences, the parameters M (reward score for a pair of matching residues; always >0) and N (penalty score for mismatching residues; always <0). For amino acid sequences, a scoring matrix is used to calculate the cumulative score. Extension of the word hits in each direction are halted when: the cumulative alignment score falls off by the quantity X from its maximum achieved value; the cumulative score goes to zero or below, due to the accumulation of one or more negative-scoring residue alignments; or the end of either sequence is reached. The BLAST algorithm parameters W, T, and X determine the sensitivity and speed of the alignment. The BLASTN program (for nucleotide sequences) uses as defaults a wordlength (W) of 11, an expectation (E) or 10, M=5, N=−4 and a comparison of both strands. For amino acid sequences, the BLASTP program uses as defaults a wordlength of 3, and expectation (E) of 10, and the BLOSUM62 scoring matrix (see Henikoff and Henikoff (1989) Proc. Natl. Acad. Sci. USA 89:10915) alignments (B) of 50, expectation (E) of 10, M=5, N=−4, and a comparison of both strands.
(53) The BLAST algorithm also performs a statistical analysis of the similarity between two sequences (see, e.g., Karlin and Altschul (1993) Proc. Natl. Acad. Sci. USA 90:5873-5787). One measure of similarity provided by the BLAST algorithm is the smallest sum probability (P(N)), which provides an indication of the probability by which a match between two nucleotide or amino acid sequences would occur by chance. For example, a nucleic acid is considered similar to a reference sequence if the smallest sum probability in a comparison of the test nucleic acid to the reference nucleic acid is less than about 0.2, more preferably less than about 0.01.
(54) The phrase “codon optimized” as it refers to genes or coding regions of nucleic acid molecules for the transformation of various hosts, refers to the alteration of codons in the gene or coding regions of polynucleic acid molecules to reflect the typical codon usage of a selected organism without altering the polypeptide encoded by the DNA. Such optimization includes replacing at least one, or more than one, or a significant number, of codons with one or more codons that are more frequently used in the genes of that selected organism.
(55) Nucleic acid is “operably linked” when it is placed into a functional relationship with another nucleic acid sequence. For example, DNA for a presequence or secretory leader is operably linked to DNA for a polypeptide if it is expressed as a preprotein that participates in the secretion of the polypeptide; a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the sequence; or a ribosome binding site is operably linked to a coding sequence if it is positioned so as to facilitate translation. Generally, “operably linked” means that the DNA sequences being linked are near each other, and, in the case of a secretory leader, contiguous and in reading phase. However, operably linked nucleic acids (e.g. enhancers and coding sequences) do not have to be contiguous. Linking is accomplished by ligation at convenient restriction sites. If such sites do not exist, the synthetic oligonucleotide adaptors or linkers are used in accordance with conventional practice. In embodiments, a promoter is operably linked with a coding sequence when it is capable of affecting (e.g. modulating relative to the absence of the promoter) the expression of a protein from that coding sequence (i.e., the coding sequence is under the transcriptional control of the promoter).
(56) “Ribosome binding site” or “RBS” is also called the Shine Dalgarno sequence and generally has a sequence complementary to the 3′ terminal of 16S rRNA. The ribosomal binding site is found in bacterial and archaeal messenger RNA, and is generally located about 8 bases upstream of the start codon AUG. In particular, the RBS sequence which appears at high frequency is AGGAGG or AAGGAGG (hereinafter these sequences are referred to as “consensus RBS sequences”), or a sequence homologous with “consensus RBS sequence”. Although these sequences appear at various sites of genes, it is understood that the RBS sequences appear at high frequency in regions upstream of start codons. Also included in the term “RBS” is the RBS sequence from the MphR gene as disclosed herein (“AGAAGG”). Other functional RBS sequences can also be used in place of the specific sequences disclosed herein. When discussing nucleotide mutations in the RBS, the first A is labeled as nucleotide “1” and the final G is labelled as nucleotide “6”. Alternatively, the mutations may sometimes referred to by their relative position to the ATG start codon. The basic structure of a prokaryote gene consists of a promoter which starts the synthesis of mRNA, a ribosome binding site which participates in the binding between mRNA and ribosomes and in the translation initiation, a start codon, a translation stop codon and a terminator which terminates the synthesis of mRNA. AUG codon is the most appropriate as a start codon. Since the start codons and coding regions are determined usually based upon a DNA sequence, in the present specification, the sequences of start codons and stop codons and sequences involved in the binding of ribosomes and mRNA are expressed as DNA sequences appropriately as well as RNA sequences, unless mentioned specifically.
(57) The term “gene” or “gene sequence” refers to the coding sequence or control sequence, or fragments thereof. A gene may include any combination of coding sequence and control sequence, or fragments thereof. Thus, a “gene” as referred to herein may be all or part of a native gene. A polynucleotide sequence as referred to herein may be used interchangeably with the term “gene”, or may include any coding sequence, non-coding, sequence or control sequence, fragments thereof, and combinations thereof. The term “gene” or “gene sequence” includes, for example, control sequences upstream of the coding sequence (for example, the ribosome binding site).
(58) MphR Biosensors
(59) Described herein is a platform technology that comprises genetically-encoded biosensors and methods to create them for detection of a class of small molecules called polyketides. Such biosensors provide a scalable, economic, high-throughput, and broadly applicable means to specifically identify a target polyketide of interest from complex mixtures of molecules. Polyketides are used extensively as drugs to treat human, animal, and plant diseases.
(60) Examples of polyketides include, but are not limited to, macrolides, polyenes, enediynes, and aromatic polyketides. In some embodiments, the polyketide is a macrolide. In some embodiments, the polyketide is a 12-membered macrolide. In some embodiments, the polyketide is a 14-membered macrolide.
(61) Due to their widespread use, polyketides are often produced in bacteria via genetic engineering. Detection of polyketides in microbial hosts remains a significant challenge however, and this limits the throughput and success of engineering approaches aimed at improving yields of polyketide and accessing new molecules. Thus, the main application of the present invention relates to the production of antibiotics, anticancer drugs, insecticides, anti-parasitics, anti-fungals, anti-cholesterol, and immunosuppressants in microbial hosts. Because the biosensors can be employed in a wide variety of contexts, other commercial applications include but are not limited to: (1) discovery of polyketide producing genes from collections of genomes; (2) identification and quantification of polyketide-based drugs, contaminants, and other molecules in environmental, clinical, and other research samples; and (3) isolation or removal of target polyketide compounds from complex mixtures.
(62) The sensor is based on the MphR gene, which encodes a transcription factor. The natural role of wild-type (WT) MphR is to activate the expression of resistance genes in response to binding the polyketide antibiotic, erythromycin A (ErA,
(63) In one embodiment, the operator DNA sequence is 5′-AATATAACCGACGTGACTGTTACATTTAGG-3 (SEQ ID NO: 27).
(64) The genetically-encoded biosensors described here are unique in several aspects: (1) biosensors that respond to a broad variety of polyketides are not currently known; (2) biosensors that can discriminate between very closely related polyketide structures have not been described, (3) a strategy to engineer the ligand specificity and/or amount of MphR was developed that is efficient, novel, and non-obvious; and (4) other high-throughput analytical methods/tools to detect most polyketides are not available. Accordingly, high-throughput engineering approaches such as directed gene or enzyme evolution and synthetic biology have not been applied to the vast majority of polyketides due to the lack of suitable screening tools. Such strategies are critical to overcome the poor understanding of how to design and construct biosynthetic or chemical routes to new and existing antibiotics. In contrast, the biosensor-guided approach described herein can be applied to engineering the biosynthesis of a broad range of polyketides in potentially any microbial host, and could be generalized to other classes of natural products such as peptides, alkaloids, and terpenes. The invention disclosed herein can enable production of polyketide products rapidly and at lower cost than existing manufacturing routes, thus maximizing the return on investment and providing incentive to develop new antibiotics.
(65) The biosensor platform is simple (consisting of two genes—one encodes the genetically modified MphR gene sequence and the other encodes a marker/reporter gene (for example, GFP) under the control of the MphR responsive promoter), scalable (genetically encoded so that the host microbe synthesizes all the parts), economic, ultra-high-throughput (millions of potential polyketide producing strains can be assayed using the biosensor), and can be easily adapted to target polyketides of interest (directed evolution is a powerful strategy to engineer the ligand specificity of proteins).
(66) MphR is a repressor protein that controls the transcription of a gene cassette responsible for resistance to macrolide antibiotics via phosphorylation of the desosamine 2′-hydroxy group of ErA. Interestingly, MphR is also de-repressed by other macrolide antibiotics, including josamycin, oleandomycin, narbomycin, methymycin and pikromycin. This promiscuity provides a platform for creating tailored MphR variants for applications related to polyketide synthetic biology and directed evolution beyond those offered by the wild-type biosensor. For example, sensors may recognize a wide variety of polyketides, sensors may distinguish biosynthetic intermediates to allow specific detection of the desired mature product, and the binding affinity and dynamic range of a given biosensor can be tailored for specific applications.
(67) In one aspect, disclosed herein is a biosensor system comprising: a nucleic acid encoding a genetically modified MphR gene sequence, wherein the nucleic acid comprises at least one genetic mutation when compared to the wild-type MphR gene sequence; and a reporter gene whose transcription is under the control of a promoter region which is regulated by the MphR transcription factor.
(68) In some embodiments, the biosensor system further comprises a nucleic acid encoding an MphA gene sequence. In some embodiments, the biosensor system further comprises a nucleic acid encoding a portion of the mrx gene. In some embodiments, the biosensor system further comprises a nucleic acid encoding an MphA gene sequence and a portion of the mrx gene.
(69) In one embodiment, the nucleic acid encoding the genetically modified MphR gene sequence and the reporter gene are located on one recombinant DNA vector. In one embodiment, the nucleic acid encoding the genetically modified MphR gene sequence and the reporter gene are located on one recombinant DNA vector.
(70) In one embodiment, the reporter gene is a gene coding for chloramphenicol acetyltransferase, beta-galactosidase, luciferase or green fluorescent protein (GFP). In one embodiment, the reporter gene is a gene coding for green fluorescent protein (GFP). In one embodiment, the reporter gene is a gene coding for chloramphenicol acetyltransferase.
(71) In some embodiments, the MphR mutation confers improved sensitivity for detecting erythromycin A. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1G, A1T, A1C, G2T, G2A, A3C, A3G, A4T, G5T, G6T, or a combination thereof. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1G, A4T, or a combination thereof. In one embodiment, the MphR genetic mutation encodes an A1G nucleotide change in the ribosome binding site sequence. In one embodiment, the MphR genetic mutation encodes an A4T nucleotide change in the ribosome binding site sequence.
(72) In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1T, G2T, A3C, or a combination thereof. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1C, G2T, A3G, or a combination thereof. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from G2A, G5T, or a combination thereof.
(73) In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T17R, T27G, Q65M, T27A, M59E, M59S, R22H, K35N, T49I, L89V, D98N, E109D, R122T, K132N, A151T, H184Q, T49I, L89V, D98N, E109D, or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T17R, T27G, Q65M, T27A, M59E, M59S, R22H, K35N, or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T49I, L89V, D98N, E109D, R122T, K132N, A151T, H184Q, T49I, L89V, D98N, E109D, or a combination thereof.
(74) In some embodiments, the MphR mutation confers improved selectivity for detecting erythromycin A in comparison to other polyketides. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from A16T, T154M, M155K, or a combination thereof. In one embodiment, the MphR genetic mutation encodes an A4T nucleotide change in the ribosome binding site sequence and an amino acid change selected from A16T, T154M, M155K, or a combination thereof.
(75) In some embodiments, the MphR mutation confers improved selectivity for detecting erythromycin A in comparison to structurally similar precursors. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from P4L, W107L, H193R, or a combination thereof.
(76) In some embodiments, the MphR mutation confers improved sensitivity for detecting pikromycin. In one embodiment, the MphR genetic mutation encodes the amino acid change S106F.
(77) In some embodiments, the MphR mutation confers improved sensitivity for detecting narbomycin. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from V33L, A34S, R51C, or a combination thereof.
(78) In some embodiments, the MphR mutation confers improved sensitivity for detecting clarithromycin. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T49I, L89V, D98N, E109D or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change R122T. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from R122T, K132N, A151T, H184Q, or a combination thereof. In one embodiment, the MphR genetic mutation encodes an A4T nucleotide change in the ribosome binding site sequence and an amino acid change selected from R122T, K132N, A151T, H184Q, or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T49I, L89V, D98N, E109D, or a combination thereof.
(79) In one aspect, disclosed herein is a genetically modified host cell comprising: a nucleic acid encoding a genetically modified MphR gene sequence, wherein the nucleic acid comprises at least one genetic mutation when compared to the wild-type MphR gene sequence; and a reporter gene whose transcription is under the control of a promoter region which is regulated by the MphR transcription factor.
(80) In one embodiment, the nucleic acid encoding the genetically modified MphR gene sequence and the reporter gene are located on one recombinant DNA vector.
(81) In one embodiment, the nucleic acid encoding the genetically modified MphR gene sequence and the reporter gene are located on one recombinant DNA vector.
(82) In one embodiment, the reporter gene is a gene coding for chloramphenicol acetyltransferase, beta-galactosidase, luciferase or green fluorescent protein (GFP). In one embodiment, the reporter gene is a gene coding for green fluorescent protein (GFP). In one embodiment, the reporter gene is a gene coding for chloramphenicol acetyltransferase.
(83) In one embodiment, the cell is E. coli. In one embodiment, the cell is Streptomyces. In one embodiment, the cell is Streptomyces venezuelae. In one embodiment, the cell is Saccharopolyspora erythraea.
(84) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the nucleotide sequence upstream of the ATG start codon of the MphR gene sequence, wherein the mutation confers increased sensitivity for detection of erythromycin A in comparison to the wild type MphR transcription factor.
(85) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the ribosome binding site sequence of the MphR gene sequence, wherein the mutation confers increased sensitivity for detection of erythromycin A in comparison to the wild type MphR transcription factor.
(86) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the MphR protein sequence, wherein the mutation confers increased sensitivity for detection of erythromycin A in comparison to the wild type MphR transcription factor.
(87) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the nucleotide sequence upstream of the ATG start codon of the MphR gene sequence, wherein the mutation confers increased sensitivity for detection of erythromycin A in comparison to the wild type MphR transcription factor.
(88) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the ribosome binding site sequence of the MphR gene sequence, wherein the mutation confers increased sensitivity for detection of erythromycin A in comparison to the wild type MphR transcription factor.
(89) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the MphR protein sequence, wherein the mutation confers increased selectivity for detection of erythromycin A in comparison to other polyketides.
(90) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the MphR protein sequence, wherein the mutation confers increased selectivity for detection of erythromycin A in comparison to structurally similar precursors.
(91) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the MphR protein sequence, wherein the mutation confers increased sensitivity for detection of pikromycin in comparison to the wild type MphR transcription factor.
(92) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the nucleotide sequence upstream of the ATG start codon of the MphR gene sequence, wherein the mutation confers increased sensitivity for detection of pikromycin in comparison to the wild type MphR transcription factor.
(93) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the ribosome binding site sequence of the MphR gene sequence, wherein the mutation confers increased sensitivity for detection of pikromycin in comparison to the wild type MphR transcription factor.
(94) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the MphR protein sequence, wherein the mutation confers increased sensitivity for detection of narbomycin in comparison to the wild type MphR transcription factor.
(95) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the nucleotide sequence upstream of the ATG start codon of the MphR gene sequence, wherein the mutation confers increased sensitivity for detection of narbomycin in comparison to the wild type MphR transcription factor.
(96) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the ribosome binding site sequence of the MphR gene sequence, wherein the mutation confers increased sensitivity for detection of narbomycin in comparison to the wild type MphR transcription factor.
(97) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the MphR protein sequence, wherein the mutation confers increased sensitivity for detection of YC-17 in comparison to the wild type MphR transcription factor.
(98) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the nucleotide sequence upstream of the ATG start codon of the MphR gene sequence, wherein the mutation confers increased sensitivity for detection of YC-17 in comparison to the wild type MphR transcription factor.
(99) In some embodiments, disclosed herein is a genetically modified MphR gene sequence comprising at least one mutation in the ribosome binding site sequence of the MphR gene sequence, wherein the mutation confers increased sensitivity for detection of YC-17 in comparison to the wild type MphR transcription factor.
(100) In one aspect, disclosed herein is a biosensor system comprising: a nucleic acid encoding a genetically modified MphR transcription factor, wherein the nucleic acid comprises at least one genetic mutation when compared to the wild-type MphR gene sequence; and a reporter gene whose transcription is under the control of a promoter region which is regulated by the MphR transcription factor.
(101) In one aspect, disclosed herein is a genetically modified host cell comprising: a nucleic acid encoding a genetically modified MphR transcription factor, wherein the nucleic acid comprises at least one genetic mutation when compared to the wild-type MphR gene sequence; and a reporter gene whose transcription is under the control of a promoter region which is regulated by the MphR transcription factor.
(102) In one aspect, provided herein is a method for detecting a polyketide, comprising: introducing into a cell: i. a nucleic acid encoding a genetically modified MphR transcription factor, wherein the nucleic acid comprises at least one genetic mutation when compared to the wild-type MphR gene sequence; and ii. a reporter gene whose transcription is under the control of a promoter region which is regulated by the MphR transcription factor; and detecting the polyketide based on the differential expression of the reporter gene in comparison to a cell comprising a wild-type MphR transcription factor.
(103) In one aspect, provided herein is a method of screening for genetic mutations in a target gene, comprising: introducing into a cell: i. a nucleic acid encoding a genetically modified MphR transcription factor, wherein the nucleic acid comprises at least one genetic mutation when compared to the wild-type MphR gene sequence; and ii. a reporter gene whose transcription is under the control of a promoter region which is regulated by the MphR transcription factor; introducing at least one mutation into a target gene; and identifying a cell comprising the target gene mutation based on the differential expression of the reporter gene in comparison to a cell comprising the wild-type target gene.
MphR Biosensors: Methods
(104) In one aspect, provided herein is a method for detecting a polyketide, comprising: introducing into a cell: i. a nucleic acid encoding a genetically modified MphR gene sequence, wherein the nucleic acid comprises at least one genetic mutation when compared to the wild-type MphR gene sequence; and ii. a reporter gene whose transcription is under the control of a promoter region which is regulated by the MphR transcription factor; and detecting the polyketide based on the differential expression of the reporter gene in comparison to a cell comprising a wild-type MphR gene sequence.
(105) In one embodiment, the nucleic acid encoding the genetically modified MphR gene sequence and the reporter gene are located on one recombinant DNA vector.
(106) In one embodiment, the reporter gene is a gene coding for chloramphenicol acetyltransferase, beta-galactosidase, luciferase or green fluorescent protein (GFP). In one embodiment, the reporter gene is a gene coding for green fluorescent protein (GFP).
(107) In some embodiments, the MphR mutation confers improved sensitivity for detecting erythromycin A. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1G, A1T, A1C, G2T, G2A, A3C, A3G, A4T, G5T, G6T, or a combination thereof. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1G, A4T, or a combination thereof. In one embodiment, the MphR genetic mutation encodes an A1G nucleotide change in the ribosome binding site sequence. In one embodiment, the MphR genetic mutation encodes an A4T nucleotide change in the ribosome binding site sequence.
(108) In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1T, G2T, A3C, or a combination thereof. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1C, G2T, A3G, or a combination thereof. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from G2A, G5T, or a combination thereof.
(109) In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T17R, T27G, Q65M, T27A, M59E, M59S, R22H, K35N, T49I, L89V, D98N, E109D, R122T, K132N, A151T, H184Q, T49I, L89V, D98N, E109D, or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T17R, T27G, Q65M, T27A, M59E, M59S, R22H, K35N, or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T49I, L89V, D98N, E109D, R122T, K132N, A151T, H184Q, T49I, L89V, D98N, E109D, or a combination thereof.
(110) In some embodiments, the MphR mutation confers improved selectivity for detecting erythromycin A in comparison to other polyketides. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from A16T, T154M, M155K, or a combination thereof. In one embodiment, the MphR genetic mutation encodes an A4T nucleotide change in the ribosome binding site sequence and an amino acid change selected from A16T, T154M, M155K, or a combination thereof.
(111) In some embodiments, the MphR mutation confers improved selectivity for detecting erythromycin A in comparison to structurally similar precursors. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from P4L, W107L, H193R, or a combination thereof.
(112) In some embodiments, the MphR mutation confers improved sensitivity for detecting pikromycin. In one embodiment, the MphR genetic mutation encodes the amino acid change S106F.
(113) In some embodiments, the MphR mutation confers improved sensitivity for detecting narbomycin. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from V33L, A34S, R51C, or a combination thereof.
(114) In some embodiments, the MphR mutation confers improved sensitivity for detecting clarithromycin. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T49I, L89V, D98N, E109D or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change R122T. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from R122T, K132N, A151T, H184Q, or a combination thereof. In one embodiment, the MphR genetic mutation encodes an A4T nucleotide change in the ribosome binding site sequence and an amino acid change selected from R122T, K132N, A151T, H184Q, or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T49I, L89V, D98N, E109D, or a combination thereof.
(115) In one embodiment, the cell is E. coli. In one embodiment, the cell is Streptomyces. In one embodiment, the cell is Streptomyces venezuelae.
(116) In one aspect, provided herein is a method of screening for genetic mutations in a target gene, comprising: introducing into a cell: i. a nucleic acid encoding a genetically modified MphR gene sequence, wherein the nucleic acid comprises at least one genetic mutation when compared to the wild-type MphR gene sequence; and ii. a reporter gene whose transcription is under the control of a promoter region which is regulated by the MphR transcription factor; introducing at least one mutation into a target gene; and identifying a cell comprising the target gene mutation based on the differential expression of the reporter gene in comparison to a cell comprising the wild-type target gene.
(117) In one embodiment, the reporter gene is a gene coding for chloramphenicol acetyltransferase, beta-galactosidase, luciferase or green fluorescent protein (GFP). In one embodiment, the reporter gene is a gene coding for green fluorescent protein (GFP).
(118) In some embodiments, the MphR mutation confers improved sensitivity for detecting erythromycin A. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1G, A1T, A1C, G2T, G2A, A3C, A3G, A4T, G5T, G6T, or a combination thereof. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1G, A4T, or a combination thereof. In one embodiment, the MphR genetic mutation encodes an A1G nucleotide change in the ribosome binding site sequence. In one embodiment, the MphR genetic mutation encodes an A4T nucleotide change in the ribosome binding site sequence.
(119) In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1T, G2T, A3C, or a combination thereof. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from A1C, G2T, A3G, or a combination thereof. In one embodiment, the MphR genetic mutation encodes a nucleotide change in the ribosome binding site sequence selected from G2A, G5T, or a combination thereof.
(120) In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T17R, T27G, Q65M, T27A, M59E, M59S, R22H, K35N, T49I, L89V, D98N, E109D, R122T, K132N, A151T, H184Q, T49I, L89V, D98N, E109D, or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T17R, T27G, Q65M, T27A, M59E, M59S, R22H, K35N, or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T49I, L89V, D98N, E109D, R122T, K132N, A151T, H184Q, T49I, L89V, D98N, E109D, or a combination thereof.
(121) In some embodiments, the MphR mutation confers improved selectivity for detecting erythromycin A in comparison to other polyketides. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from A16T, T154M, M155K, or a combination thereof. In one embodiment, the MphR genetic mutation encodes an A4T nucleotide change in the ribosome binding site sequence and an amino acid change selected from A16T, T154M, M155K, or a combination thereof.
(122) In some embodiments, the MphR mutation confers improved selectivity for detecting erythromycin A in comparison to structurally similar precursors. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from P4L, W107L, H193R, or a combination thereof.
(123) In some embodiments, the MphR mutation confers improved sensitivity for detecting pikromycin. In one embodiment, the MphR genetic mutation encodes the amino acid change S106F.
(124) In some embodiments, the MphR mutation confers improved sensitivity for detecting narbomycin. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from V33L, A34S, R51C, or a combination thereof.
(125) In some embodiments, the MphR mutation confers improved sensitivity for detecting clarithromycin. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T49I, L89V, D98N, E109D or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change R122T. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from R122T, K132N, A151T, H184Q, or a combination thereof. In one embodiment, the MphR genetic mutation encodes an A4T nucleotide change in the ribosome binding site sequence and an amino acid change selected from R122T, K132N, A151T, H184Q, or a combination thereof. In one embodiment, the MphR genetic mutation encodes the amino acid change selected from T49I, L89V, D98N, E109D, or a combination thereof.
EXAMPLES
(126) The following examples are set forth below to illustrate the systems, cells, methods, compositions and results according to the disclosed subject matter. These examples are not intended to be inclusive of all aspects of the subject matter disclosed herein, but rather to illustrate representative systems, cells, methods, compositions and results. These examples are not intended to exclude equivalents and variations of the present invention which are apparent to one skilled in the art.
Example 1
MphR Biosensors with Improved Sensitivity for Erythromycin A (ErA)
(127) The sensitivity of biosensors often requires tailoring to meet specific needs. For example, if a certain polyketide is expected to be found inside microbial cells at concentrations between 0 and 100 μM, then a biosensor is required that displays a linear detection response within the same range. The wild-type MphR gene was subjected to a directed evolution approach in order to identify MphR gene mutations and variants with improved sensitivity towards ErA. A library of MphR gene mutations and variants was created by error-prone PCR (epPCR). Because many mutations could lead to misfolded MphR variants or those that do not bind to the operator, flow cytometry was first used to remove variants that are always ‘ON’ in the absence of ligand. Next, individual ‘OFF’ variants were tested in wells of microplates to identify the variants most improved at low concentrations of ErA. Next, using promising individual variants, GFP fluorescence was measured in the presence of varying concentrations of erythromycin A (ErA) and the data was fit to the Hill equation to provide several parameters for describing selected MphR variants: dynamic range (GFP.sub.max-GFP.sub.min), K.sub.1/2 (ligand conc. resulting in half-maximal induction), cooperativity (Hill coefficient), linear range of detection, and Z′-factor (score of 0.50 indicates an excellent screen). Three variants (H4, A3, and E7) displayed improvements in sensitivity (
(128) Additional mutations in the MphR gene sequence that provided increased sensitivity to erythromycin A (ErA) were also identified. The MphR macrolide resistance cassette operates as an analog converter of macrolide concentration to antibiotic resistance, as explained above and elsewhere ((Noguchi N, et al. Regulation of Transcription of the mph(A) Gene for Macrolide 2′-Phosphotransferase I in Escherichia Coli; Characterization of the Regulatory Gene mphR(A). Journal of Bacteriology. 2000; 182(18):5052-5058) (Zheng J, et al. Structure and Function of the Macrolide Biosensor Protein, MphR(A), With and Without Erythromycin. Journal of Molecular Biology. 2009; 387(5):1250-60). Refactoring the MphR cassette as a two plasmid system with a GFP reporter (Gardner L, et al. Photochemical Control of Bacterial Signal Processing Using a Light-activated Erythromycin. Molecular Biosystems. 2011; 7(9):2554-7) created a biosensor capable of detecting a range of macrolides. Previous literature reports various induction ranges for MphR-based biosensors depending on the plasmid construct. Church and coworkers reported K.sub.1/2 values of 22 and 97 μM erythromycin A for low and high copy number plasmids respectively, using a GFP reporter (Rogers, J. et al. 7648-7660 Nucleic Acids Research, 2015, Vol. 43, No. 15). Eberz and coworkers report an apparent induction range of 0 (min luminescence) to 20 (max luminescence) μM erythromycin A with an approximate half maximal induction at 10 μM using the LuxABCDE luminescence reporter system (Mohrle, V. et al. Anal. Bioanal. Chem. 2007 July; 388(5-6):1117-25). In the experiments conducted herein, a previously reported MphR-based biosensor (MphR-WT) (Gardner L, et al. Photochemical Control of Bacterial Signal Processing Using a Light-activated Erythromycin. Molecular Biosystems. 2011; 7(9):2554-7) had a K.sub.1/2 of only 2.73 μM erythromycin A (Table 1) using a GFP reporter. Error-prone and multi-site saturation mutagenesis of the MphR gene was performed in order to improve sensitivity to erythromycin A.
(129) Plasmid pMLGFP (See
(130) The best performing clones from each library were selected for further analysis. Dose-response experiments revealed clones with improved performance features compared to MphR-WT for erythromycin A sensitivity (
(131) TABLE-US-00001 TABLE 1 Biosensor Performance Features for MphR Mutations. linear range K.sub.1/2 dynamic range of detection Clone (μm) Cooperativity (GFP.sub.max-GFP.sub.min) (μM) G76C 0.42 ± 0.01 1.80 ± 0.01 59000 .sup. 0.1-0.6 V90I 0.55 ± 0.01 2.84 ± 0.42 58600 0.1-1 T17R 0.93 ± 0.03 3.16 ± 0.13 59300 0.3-1 T27G/ 1.55 ± 0.09 2.92 ± 0.17 60200 0.6-2 Q65M T27A/ 1.15 ± 0.09 2.59 ± 0.04 54800 0.1-2 M59E WT 2.73 ± 0.72 4.44 ± 1.52 54800 0.9-5
(132) In Table 1, Hill functions were used to derive biosensor transfer functions. K.sub.1/2 is the inducer concentration at half maximal induction. Cooperativity is derived from the Hill function to indicate cooperative ligand binding between protein monomers of the MphR dimer. Dynamic range is the GFP maximal response minus the minimum GFP response, which in all cases was the response with no ligand. The linear range of detection is the linear portion of the dose-response curve with a slope R.sup.2=0.95 or higher.
(133) Importantly, several of these sensors have linear detection ranges capable of detecting titers of erythromycin A heterologously produced in shake-flask E. coli cultures. As this has remained a preferred method for the production of erythromycin A and erythromycin A derivatives resulting from precursor-directed mutasynthesis (Sundermann U, et al. Enzyme-directed Mutasynthesis: a Combined Experimental and Theoretical Approach to Substrate Recognition of a Polyketide Synthase. ACS Chemical Biology. 2013; 8(2):443-50) or domain-swapping biosynthesis (Jiang M., Pfeifer, B. Metabolic and Pathway Engineering to Influence Native and Altered Erythromycin Production Through E. coli. Metabolic Engineering. 2013; 19:42-9), MphR biosensors can be used in high-throughput approaches to the continued improvement of heterologous erythromycin A biosynthetic engineering.
(134) After further analysis of these clones, via DNA sequencing, the ribosome binding site (RBS) of A3 and E7 were found to be mutated, compared to the wild-type MphR sequence. Clone H4 also had mutations in other portions of the sequence and thus was omitted from further analysis here. This implicates the RBS mutations in these variants are responsible for sensitivity to erythromycin, rather than the amino acid changes identified. To confirm this, new versions of A3 and E7 were constructed that either only included the RBS mutations or the amino acids for each clone. Subsequent analysis revealed that the RBS mutations alone were responsible for the improvement in sensitivity to erythromycin (
(135) TABLE-US-00002 TABLE 2 Sensitivity of wild-type MphR and ribosome binding site (RBS)-only mutations towards erythromycin A WT WT A3-RBS WT E7-RBS K.sub.1/2 (μM) 1.9 ± 0.03 0.52 ± 0.02 0.64 ± 0.02
(136) TABLE-US-00003 TABLE 3 Sensitivity of wild-type MphR and amino-acid change-only mutations towards erythromycin A WT-AA A3-AA E7-AA K.sub.1/2 (μM) 1.9 ± 0.03 1.9 ± 0.02 2.2 ± 0.03
Example 2
Engineering Sensitivity Towards Erythromycin Via Ribosome Binding Site (RBS) Mutagenesis of MphR
(137) The finding that mutations to the ribosome binding site (RBS) of clones A3 and E7 were responsible for modulating sensitivity prompted the inventors to make a dedicated library of RBS mutations to search for biosensors with improved sensitivities. Screening the “smRBS” library and analysis of the best performing clones revealed three clones (see below) with significantly improved sensitivity towards erythromycin. The best clone, smRBSA1, outperforms each mutant previously described (
(138) TABLE-US-00004 TABLE 4 Sensitivity of smRBS mutants with erythromycin A. Clone RBS K.sub.1/2 (μm) DR (GFP) LRD (μM) Hill.sub.c MphR-WT AGAAGGT 1.88 ± 0.03 66000 0.9-5 3.6 ± 0.3 smRBS1A1 TTCAGGT 0.19 ± 0.02 66000 0.01-0.7 1.7 ± 0.1 smRBS1G6 CTGAGGT 0.91 ± 0.04 64000 0.3-2 5.4 ± 1.2 smRBS2E1 AAAGGTT 1.44 ± 0.08 63000 0.3-3 3.9 ± 0.5 ‘DR’ is the dynamic range, GFP.sub.max-GFP.sub.min; ‘LRD’ is the linear range of detection.
(139) TABLE-US-00005 TABLE 5 E7-RBS, smRBS1A1, pikB1, and WT with pikromycin Clone K.sub.1/2 (μm) Hill.sub.C Dyn. Range (RFU) WT 97 ± 2 2.9 ± 0.3 26800 ± 400 E7-RBS 50 ± 20 2.3 ± 0.1 40000 ± 5000 smRBS1A1 48 ± 5 2.5 ± 0.2 37000 ± 6000 pikB1 0.81 ± 0.02 1.8 ± 0.2 64000 ± 2000
Example 3
MphR Biosensors with Improved Selectivity Towards ErA
(140) In many cases, it is necessary to determine the presence and concentration of a given polyketide in the presence of other structurally related molecules. Accordingly, the selectivity of MphR requires tailoring towards target molecules. To test the capacity of random mutations to alter the ligand specificity of MphR, the initial goal was to find variants that were more selective with erythromycin A compared to clarithromycin, azithromycin, and roxithromycin. A library of MphR gene mutations and variants was created by error-prone PCR (epPCR) and flow cytometry was first used to remove variants that are always ‘ON’ in the absence of erythromycin A and the presence of clarithromycin and azithromycin. Next, individual ‘OFF’ variants were tested in wells of microplates to identify the variants most improved at low concentrations of erythromycin A. Thus, some of the ‘OFF’ library members were duplicated and each screened in the presence of erythromycin A or a mixture of clarithromycin, azithromycin, and roxithromycin. Several variants were not activated by clarithromycin, azithromycin, and roxithromycin but were strongly activated by erythromycin A (
(141) To confirm previous reports of the broad inducer tolerance of the MphR biosensor (Eberz 2007), erythromycin A and several clinically useful semi-synthetic macrolides were screened versus MphR-WT. In liquid culture, dose-dependent MphR-WT activations for erythromycin A (compound 1), clarithromycin (compound 2), azithromycin (compound 3), and roxithromycin (compound 4) were obtained (
(142) Clarithromycin is an erythromycin A semi-synthetic analog that differs by a single methoxy in place of a hydroxyl group at the C-6 carbon of the polyketide core macrolactone. Azithromycin is an erythromycin analog synthesized by an oxime-mediated nitrogen insertion and ring expansion at C-9 of the polyketide backbone. Roxithromycin replaces the C-9 ketone of erythromycin A with an imine-linked polyester. Clarithromycin, azithromycin and roxithromycin are semi-synthetic products of microbially produced erythromycin A. Distinction between erythromycin A and these modified analogs has thus far relied on inherently low-throughput techniques such as LC-MS, HPLC and NMR.
(143) Biosensors capable of selective detection of specific macrolides from laboratory, industrial or environmental samples are useful in improving biotransformations, increasing final titers by detecting biosynthetic bottlenecks, and identifying macrolide contaminants.
(144) Clone MphR-A16T/T154M/M155K (Clone M2D6) demonstrated exceptional selectivity for erythromycin A versus the three semi-synthetic analogs. Dose-response analysis revealed MphR-A16T/T154M/M155K maintained a K.sub.1/2 of 5.54 μM for erythromycin A, but displayed little to no activation by clarithromycin, azithromycin and roxithromycin. As summarized in Table 6 and
(145) TABLE-US-00006 TABLE 6 K.sub.1/2 values of MphR-WT and MphR- A16T/T154M/M155K with erythromycin A, clarithromycin, azithromycin and roxithromycin. K.sub.1/2 1 2 3 4 WT 2.03 ± 0.10 2.69 ± 0.14 0.60 ± 0.02 67.16 ± 3.41 A16T/T154M/ 5.54 ± 0.53 20.10 ± 0.28 N.C. N.C. M155K
(146) In Table 6, Compounds are numbered above their corresponding K.sub.1/2 value of each numbered compound (erythromycin A (1), clarithromycin (2), azithromycin (3) and roxithromycin(4)). MphR-A16T/T154M/M155K demonstrated much higher selectivity for erythromycin A versus its semi-synthetic counterparts compared to the wild-type biosensor.
(147) MphR-A16T/T154M/M155K's ability to discriminate between closely related compounds that structurally differ by as little as a methyl substituent demonstrate the powerful application mutagenesis and high-throughput screen (HTS) have on developing tailored biosensors. Biosensors with specific ligand activation selectivities as demonstrated here are useful tools for monitoring reaction conversions in the production of erythromycin A analogs and in screening environmental samples for specific macrolide contaminants.
(148) The RBS mutations from the erythromycin sensitive variant E7 were transferred to the MphR variant M2D6, which was previously engineering to be specific for erythromycin A. This new variant MphR M2D6-E7RBS displayed 2-fold enhanced sensitivity towards erythromycin A, but with negligible change in sensitivity towards semi-synthetic derivatives (analogues) (
(149) TABLE-US-00007 TABLE 7 E7RBS-M2D6 compared to WT and M2D6 Erythromycin K.sub.1/2 Dynamic Selectivity (ErA) (μM) range (K.sub.1/2ErA/K.sub.1/2analogue) WT 1.98 67000 — M2D6 4.84 39000 — M2D6-E7RBS 2.63 49000 — K.sub.1/2 Dynamic (μM) range Selectivity Clarithromycin WT 2.00 64000 0.99 M2D6 21.51 7000 0.23 M2D6-E7RBS 12.67 16000 0.21 Azithromycin WT 0.60 28000 N.C. M2D6 N.C. 0 N.C. M2D6-E7RBS N.C. 0 N.C. Roxithromycin WT 74.08 32000 N.C. M2D6 N.C. 0 N.C. M2D6-E7RBS N.C. 0 N.C.
Example 4
Biosensors for Detection of Macrolide Glycosylation
(150) The ability for MphR or MphR gene variants thereof to discriminate between closely related polyketides provides opportunities to report the activity of enzymes which catalyze the transformation of a polyketide not detected by MphR into a product that is detected by MphR. For example, MphR may specifically recognize the sugar residues attached to detected polyketides. Thus, MphR likely does not detect the corresponding aglycones. To test this, the aglycone 6-deoxyerythronolide B (6dEB) was produced via an engineered E. coli strain and purified by flash chromatography. The identity of the compound was confirmed by comparison of the .sup.13C/.sup.1H-NMR spectral data to that published, by high-resolution mass analysis (6 dEB calc. [M+Na].sup.+ m/z=409.25664; 6dEB obs. [M+Na].sup.+ m/z=409.25525), and by comparison to authentic biosynthetic and synthetic standards. Next, the ability of 6 dEB to activate GFP expression under control of WT MphR was tested. As predicted, the aglycone failed to activate GFP expression, whereas the corresponding glycoside erythromycin A is a good activator (
Example 5
Expanding the Synthetic Scope of Polyketide Glycosylation Machinery by Directed Evolution
(151) The stringent substrate specificity of natural product glycosyltransferases (GTs) severely restricts the scope of polyketide glycodiversification strategies. Directed evolution is used to expand the specificity of macrolide GTs. The specificity of MphR towards desosaminylated macrolides can be leveraged as a sensor to report glycosylation and identify GT variants with improved activity and substrate specificity. Libraries of GT variants can be challenged with diverse substrates and screening via the MphR biosensor. By testing the function of many GT variants using MphR, potentially any GT can be engineered. These described methods can produce variant GTs with broad specificities beyond those originally screened for, the creation of new tools for glycoside synthesis and a new approach for engineering natural product GTs.
(152) Anthracyclines (e.g. doxorubicin), enediynes (e.g. calicheamicin), avermectins (e.g. avermectin B.sub.1a), polyenes (nystatin A.sub.1), and perhaps most notably, macrolides are examples of glycosylated polyketides. The sugars of macrolide antibiotics such as erythromycin A are absolutely essential for the ability of macrolides to inhibit protein synthesis at the ribosome and the corresponding aglycone is not an effective antibiotic. In fact, altering the glycosylation pattern of macrolides can even change the biological activity from antimicrobial to anti-viral or anti-parasitic. Glycosylated polyketides have also been used as probes to perturb biological function. Classical chemical approaches for the synthesis of glycoconjugates are challenging since regio- and stereochemical control of glycosidic linkage formation requires multiple protection/deprotection steps, typically resulting in poor yields. On the other hand, biosynthetic approaches for glycoconjugate synthesis are an attractive alternative to traditional chemical synthesis, since enzymes are usually highly regio- and stereoselective and do not require complex protection strategies. Moreover, approaches that involve enzymes are particularly promising given the potential to produce multi-gram scale quantities of natural products via bacterial fermentation, at low cost, and with minimal use of organic solvents. Accordingly, biosynthetic pathways responsible for the synthesis of glycosylated polyketides have been intensively investigated as tools for the production of glycosides. Glycosylation, which is often rate limiting, is achieved through the transfer of a sugar moiety from an activated glycosyl-donor, usually in form of a nucleotide diphosphate (NDP)-sugar, and is catalyzed by glycosyltransferases (GTs) (
Example 6
Biosensors for Detection of Erythromycin A C6 O-Methylation
(153) Erythromycin A is one of most widely prescribed macrolide antibiotics. Yet, its poor bioavailability and limited spectrum of activity have spurred tremendous efforts to alter the structure of erythromycin A and have resulted in the development of several generations of novel antibiotics. For example, the second generation macrolide antibiotic 6-O-methylerythromycin (clarithromycin,
(154) For example, an O-methyltransferase (OMT) could afford clarithromycin in a single step from erythromycin A (
(155) A genetic selection to identify OMT variants from large combinatorial libraries of OMT mutants can be used. Directed evolution and selections are known strategies for dramatically altering enzyme regio- and substrate specificity. The key challenge is that screening/selection methods with the requisite throughput or general applicability are not available for natural product OMTs. There are no reported ultra-high-throughput screens for methyltransferases. Most polyketides are not chromophores or fluorophores and don't offer a spectrophotometric change upon methylation that could be monitored. Moreover, methylation typically does not provide a suitable phenotype that can be leveraged for a screen or selection. Mass spectrometry is suitable for screening relatively small libraries of variants when the requisite instrumentation and expertise is available. Regardless, the ability of high-throughput mass spectrometry to quantify polyketides in complex mixtures and to distinguish congeners is unproven. Moreover, identification of suitable OMTs for the biosynthesis of clarithromycin might require the ability to screen hundreds of thousands of variants (if not more), a throughput that is well out of the range of liquid chromatography. To address this need, an MphR sensor is generated that is activated by clarithromycin but not erythromycin A. Given OMT libraries expressed in E. coli are fed with erythromycin A, and E. coli is not able to modify the structure of erythromycin A, the sensor must be selective for clarithromycin in the presence of erythromycin A, and the reporter MphR signal should be low (ideally zero) in the presence of erythromycin A.
(156) Directed evolution has been used here to alter the ligand specificity of MphR. A library of MphR variants was created by error-prone PCR (epPCR). Reasoning that many mutations could lead to misfolded variants or those that do not bind to the operator, and that variants are required that are not activated by ErA, fluorescent activated cell sorting (FACS) was first used to remove those variants that were constitutively ‘ON’ in the presence of ErA. To test the capacity of random mutations to alter the ligand specificity of MphR, the initial goal was to find variants that were more selective with clarithromycin compared to erythromycin A. Thus, some of the ‘OFF’ library members were duplicated and each screened in the presence of clarithromycin and erythromycin A. Several variants were identified that showed higher GFP reporter signals in the presence of clarithromycin compared to erythromycin A. One particular clone, “M1B10” (comprising amino acid changes T49I, L89V, D98N, E109D) was selected for further analysis. GFP fluorescence was measured in the presence of varying concentrations of erythromycin A or clarithromycin (0.1-150 μM) and showed that the selectivity of this MphR variant was now shifted towards clarithromycin. For example, at 10 μM ligand, the fluorescence response with clarithromycin is 10-fold higher than with erythromycin A (
(157) MphR M1B10 was replaced by the variant “M9C4.” MphR WT was subjected to structural-guided mutagenesis (R122T mutation), and error-prone PCR based on R122T mutation, yielding the variant “M9C4”. This variant is the most clarithromycin/erythromycin selective biosensor reported to date. At 10 μM ligand, the fluorescence response with clarithromycin is 29-fold higher than with erythromycin A. The RBS of the variant E7 was included (E7_M9C4), further improving sensitivity (
(158) TABLE-US-00008 TABLE 8 M9C4 clarithromycin specific biosensor Dynamic range K.sub.1/2 Selectivity Hill Mutation Ligand (RFUmax-RFUmin) (μM) (K.sub.1/2ErA/K.sub.1/2Clarithromycin) coefficient WT ErA 52125 1.51 0.92 3.52 Clari 52749 1.64 2.30 R122T ErA 3666 47.09 1.94 2.39 Clari 5751 24.22 3.03 M9C4 ErA 11342 68.32 6.74 2.03 Clari 33326 10.14 1.49 E7_M9C4 ErA 15318 29.33 6.01 1.95 Clari 46345 4.88 1.49
Example 7
Identification of Enzymes for Synthesis of Clarithromycin
(159) The objective here is to utilize MphR variants that recognize semi-synthetic polyketide analogues to identify enzymes for their chemo-enzymatic synthesis. MphR-based sensors can be used to identify and enrich novel polyketide tailoring enzymes by sensing the production of the desired product in vivo. An MphR variant specific for 6-O-methylerythromycin (clarithromycin) is generated and in vivo selections are performed to identify novel O-methyltransferases (OMTs) that enable the in vivo production of this valuable semi-synthetic derivative. Such enzymatic activity is difficult or impossible to identify without a genetically encoded biosensor and this approach could afford an array of other semi-synthetic derivatives.
(160) Several candidate OMTs have been identified for directed evolution. EryG is a candidate given it already recognizes the desired substrate, albeit in a different conformation than required. EryG has been expressed in E. coli and displays some macrolide promiscuity. Given a crystal structure for EryG is not available, Phyre2 and I-TASSER were used to generate homology models. The conserved SAM-binding site was identified by Phyre2 and I-TASSER, while the putative macrolide-binding site were identified by comparison to known OMT sequences and acceptor-bound structures (
(161) With a clarithromycin-sensor in place, approaches for the discovery of novel OMT activity using EryG, MycF, and DnrK as scaffolds can be pursued. epPCR libraries of these enzymes are generated in addition to multi-site saturation mutagenesis at residues lining each acceptor-binding pocket (
(162) Once activity is isolated and sufficiently robust to achieve in vivo conversion, OMT variants are expressed and purified for biochemical characterization. A genetic selection could enrich OMTs that methylate the C6-OH of erythromycin A, but also other hydroxyl groups. Thus, HPLC-ELSD coupled with MS is used to determine if other products are present. However, other regiospecificities could prove useful sources of new products. Once regiospecificity of the OMT is established, full characterization (e.g. k.sub.cat, K.sub.m, stability) is determined by HPLC-ELSD, using erythromycin A, SAM, and clarithromycin as a product standard. Moreover, SAM-analogues are utilized to determine whether the evolved OMTs can be used to alkyl-diversify macrolides.
Example 8
Biosensors for Production of an Advanced Solithromycin Precursor
(163) Cempra, Inc (Chapel Hill) have completed Phase III clinical trials for solithromycin and a New Drug Application (NDA) is in progress for the treatment of community-acquired bacterial pneumonia. Solithromycin is chemically synthesized via a lengthy 19-step sequence of reactions (
(164) Precursor I can be produced in an E. coli strain because: (1) a plasmid system for expressing entire polyketide gene clusters in E. coli can be used and have demonstrated erythromycin A production; (2) suitable E. coli strains for expression of the such genes including BAP1 can be used; and (3) the natural production host cannot provide the growth speed, technical amenability, and scalability offered by E. coli. Additionally, the necessary genetic manipulations in E. coli can be performed by those skilled in the art.
(165) The artificial pathway is constructed in pieces via commercial gene synthesis, and inserted into E. coli BAP1. The prototype strain is tested by examining I in lysed cells and/or culture supernatant directly by LC-MS analysis. Notably, I is not toxic to E. coli. Subsequently, baseline I production, expected to be ˜1 mg/L culture broth, is determined by LC-MS. The MphR variant is capable of detecting I produced via the strain by measuring the GFP reporter signal. The unnatural DH/KR insertion (
(166) Given the known polyketide product titers of in vivo systems, a sensor that can detect I in the linear range 0-100 μM with a ˜50 μM K.sub.1/2 and fold-activation similar to WT MphR (with erythromycin A) is useful. Because the initial artificial pathway can produce I, albeit in poor yield, significant (e.g. >10-fold compared to initial strain) further mutations identified can provide critical proof-of-principle that biosensor-guided engineering is a viable alternative to traditional chemical synthesis of the precursor. Then, more elaborate libraries of variants can be generated and screened over multiple generations to furnish further mutations and improvements. Ultimately, product titers >1 g/L are typically needed for commercial viability of the production process.
(167) The ability of the MphR clone “PikB1” to detect a Solithromycin biosynthetic intermediate (see structure below) was determined. This biosensor can detect the intermediate at concentrations as low as 0.1 μM (
(168) ##STR00001##
Example 9
Engineering MphR Biosensors That Discriminate Between Late Stage Macrolides in Erythromycin A Biosynthesis
(169) Erythromycin A is a macrolide produced by the organized biosynthesis of type I polyketide synthase (PKS) and several late-stage tailoring enzymes. 6-Deoxyerythronolide B Synthase (DEBS) is organized as three giant polypeptides (DEBS1-3) that assemble the macrolactone 6-deoxyerythronolide B (6 dEB). 6 dEB is further tailored by P450 monooxygenases, glycosyltransferases, and a methyltransferase to yield the final product, erythromycin A (
(170) Recently reported titers of one cell biosynthesis of erythromycin A in E. coli are ˜1 mg/L (Zhang H, et al. Complete Biosynthesis of Erythromycin A and Designed Analogs Using E. coli as a Heterologous Host. Cell Chemistry & Biology. 2010; 17(11):1232-40). The impressive coordination of 26 heterologous proteins to produce a foreign natural product notwithstanding, this yield can be seen as suboptimal, since the aglycone precursor, 6 dEB, is routinely produced in E. coli shake-flask cultures exceeding 100 mg/L (Boghigian B A, et al. Multi-factorial Engineering of Heterologous Polyketide Production in Escherichia coli Reveals Complex Pathway Interactions. Biotechnology and Bioengineering. 2011; 108(6): 1360-71). Rather than solely produce the single macrolide erythromycin A, heterologous biosynthesis results in mixtures of erythromycins A, B, C and D.
(171) Typical erythromycin A biosynthesis occurs via the erythromycin C pathway. A P450 hydroxylation catalyzed by eryK converts erythromycin D to erythromycin C. Subsequently, the methyltransferase eryG catalyzes the S-adenosylmethione (SAM) dependent methylation of erythromycin C to yield erythromycin A. Erythromycin B is generally regarded as an undesired shunt product of a competing alternative pathway that reverses the order of hydroxylation and methylation of erythromycin D so that eryG methylation occurs first (Montemiglio, L C, et al. Redirecting P450 EryK Specificity by Rational Site-directed Mutagenesis. Biochemistry. 2013; 52(21) 3678-87; Savino, C, et al. Investigating the Structural Plasticity of a Cytochrome P450: Three-dimensional Structures of P450 EryK and Binding to its Physiological Substrate. Journal of Biological Chemistry. 2009; 284(42) 29170-9).
(172) Biosensor guided screening of natural or heterologous erythromycin A biosynthesis would rely of the ability of the biosensors to report the true concentration of erythromycin A without falsely over-reporting yield due to off target activation by a late-stage biosynthetic intermediate. MphR-WT was assayed for its ability to detect the late-stage biosynthetic intermediates of erythromycin biosynthesis, erythromycins B and C. Compared to erythromycin A, erythromycins B and C activate MphR-WT in a nearly identical manner (
(173) Successful application of the method above revealed MphR-P4L/W107L/H193R, a clone with enhanced erythromycin A selectivity versus erythromycin B. Compared to MphR-WT, MphR-P4L/W107L/H193R demonstrated no detectable or calculable activation by erythromycin B but retained significant erythromycin A sensitivity (
(174) TABLE-US-00009 TABLE 9 Performance features of the wild-type sensor with erythromycins A and B. linear range K.sub.1/2 dynamic range of detection MphR-WT (μm) Cooperativity (GFP.sub.max-GFP.sub.min) (μM) 1 (ErA) 1.49 3.39 52400 0.5-2.5 5 (ErB) 1.72 1.99 55800 0.3-2.5
(175) TABLE-US-00010 TABLE 10 Performance features of the P4L/W107L/H193R sensor with erythromycins A and B. MphR- P4L/ linear range W107L/ K.sub.1/2 dynamic range of detection H193R (μm) Cooperativity (GFP.sub.max-GFP.sub.min) (μM) 1 (ErA) 1.27 2.04 3800 0.3-2.5 5 (ErB) N.C. N.C. N.C. N.C.
(176) As seen in Tables 9 and 10, MphR-P4L/W107L/H193R displays a clear selectivity shift towards erythromycin A from B, while maintaining nearly the same performance features as the wild-type sensor, except dynamic range. MphR-P4L/W107L/H193R can be used as a biosensor capable of distinguishing erythromycin A from its structurally similar precursors. Sensors capable of HTS allow contemporary techniques that leverage giant library sizes to improve true erythromycin A titers. In addition to usefulness as an erythromycin A detector with less off-target activation, MphR-P4L/W107L/H193R also serves as a sensor for the detection of P450 monooxygenase eryK-catalyzed C-12 hydroxylation of erythromycin A's core. MphR-P4L/W107L/H193R and newly developed sensors of this type provide the tools necessary for high-throughput screening of late-stage tailoring enzymes in the erythromycin biosynthetic pathway.
Example 10
Engineered MphR Biosensors
(177) A summary of non-limiting examples of MphR biosensor mutations is provided in Table 11 below. A number of the mutations were discussed in the examples above. Additional mutations are shown in Table 11 that provide increased pikromycin sensitivity. Further mutations are shown in Table 11 that improved narbomycin sensitivity.
(178) ##STR00002## ##STR00003##
(179) TABLE-US-00011 TABLE 11 MphR Mutations Label Mutation Goal Effect Quantification A3 nt: A1G erythromycin A erythromycin A 3.6 times more aa: G76C sensitivity sensitivity sensitive vs. WT E7 nt: A4T erythromycin A erythromycin A 3.0 times more aa: V90I sensitivity sensitivity sensitive vs. WT smRBS1A1 nt: erythromycin A erythromycin A 9.9 times more A1T/G2T/A3C sensitivity sensitivity sensitive vs. WT QCMS3D6 T17R erythromycin A erythromycin A 2.4 times more sensitivity sensitivity sensitive vs. WT QCMS3F8 T17A/M59S erythromycin A erythromycin A 1.6 times more sensitivity sensitivity sensitive vs. WT QCMS5B4 T27G/Q65M erythromycin A erythromycin A 1.5 times more sensitivity sensitivity sensitive vs. WT QCMS5D7 T27A/M59E erythromycin A erythromycin A 2.0 times more sensitivity sensitivity sensitive vs. WT D3 (pikB1) S106F pikromycin pikromycin 118 times more sensitivity sensitivity sensitive vs. WT D3 (pikB1) S106F Solithromycin Solithromycin 52 times more precursor I precursor I sensitive vs. WT sensitivity sensitivity D3 (pikB1) S106F YC-17 sensitivity YC-17 40 times more sensitivity sensitive vs. WT YCA11 S31R YC-17 sensitivity YC-17 8.5 times more sensitivity sensitive vs. WT Nbn.YCG11 L39F YC-17 and YC-17 and 2.9 times more narbomycin narbomycin sensitive vs. WT sensitivity sensitivity NbnD11 V33L narbomycin narbomycin 2.6 times higher sensitivity sensitivity activation ratio at 5 uM than WT NbnE1 A34S narbomycin narbomycin 2.3 times higher sensitivity sensitivity activation ratio at 5 uM than WT NbnG7 R51C narbomycin narbomycin 1.7 times higher sensitivity sensitivity activation ratio at 5 uM than WT M2D6 A16T/T154M/ erythromycin A erythromycin A 20 times less M155K selectivity versus selectivity sensitive for clarithromycin, versus clarithromycin. No azithromycin, and clarithromycin, calculable roxithromycin azithromycin, activation with and azithromycin and roxithromycin roxithromycin M2D7 P4L/W107L/ erythromycin A erythromycin A No calculable H193R selectivity versus selectivity activation with erythromycin B versus erythromycin B erythromycin B C9 A34S/Y103N/ erythromycin C erythromycin C 6.8 and 13 times L189F selectivity versus selectivity less sensitive to erythromycins A versus erythromycins A and B erythromycins and B versus the A and B WT V66P V66P erythromycin A always on as Compared at 100 sensitivity tested uM erythromycin V66R V66R erythromycin A always off as Compared at 100 sensitivity tested uM erythromycin V66G V66G erythromycin A ~same Compared at 100 sensitivity activation as uM erythromycin wild-type V66I V66I erythromycin A always off as Compared at 100 sensitivity tested uM erythromycin V66D V66D erythromycin A always off as Compared at 100 sensitivity tested uM erythromycin M1B10 T49I/L89V/ clarithromycin clarithromycin 29.2 and 6.4 times D98N/E109D selectivity versus selectivity less sensitive to erythromycin A versus erythromycin A and erythromycin A clarithromycin versus the WT M9C4 R122T K132N clarithromycin clarithromycin 45.2 and 6.2 times A151T H184Q selectivity versus selectivity less sensitive to erythromycin A versus erythromycin A and erythromycin A clarithromycin versus the WT E7_M9C4 nt: A4T clarithromycin clarithromycin 19.4 and 3 times aa: R122T selectivity versus selectivity less sensitive to K132N A151T erythromycin A versus erythromycin A and H184Q and erythromycin A clarithromycin clarithromycin and versus the WT sensitivity clarithromycin sensitivity Numbering of the nt (nucleotide) mutations corresponds to the ribosome binding site sequence. For example, the RBS sequence for the MphR gene is AGAAGG. Thus, the first A is the “1”position and the final G is the “6” position of the RBS.
(180) Some of the mutations were further characterized for YC-17, narbomycin, and pikromycin selective MphR clones (
(181) TABLE-US-00012 TABLE 12 Selected sensitivity mutants with YC-17 WT A11 pikB1 G11 K.sub.1/2 19.6 ± 0.6 2.3 ± 0.1 0.49 ± 0.05 6.7 ± 0.2
(182) TABLE-US-00013 TABLE 13 Selected sensitivity mutants with Narbomycin WT D11 Activation ratio (5 uM/ 0 uM) 4 11
(183) TABLE-US-00014 TABLE 14 Selected sensitivity mutants with Pikromycin WT pikB1 K.sub.1/2 96.6 ± 2.7 0.81 ± 0.03
Example 11
Screening Erythromycin Producing Strains
(184) An erythromycin producing strain, Aeromicrobium erythreum (Reeves A R, et al. Engineering precursor flow for increased erythromycin production in Aeromicrobium erythreum. Metabolic Engineering. 2004; 6(4): 300-12; Miller E S, et al. Description of the erythromycin-producing bacterium Arthrobacter sp. strain NRRL B-3381 as Aeromicrobium erythreum gen. nov., sp. Nov. International Journal of Systematic Bacteriology. 1991; 41: 363-368), and a knock-out mutant (KO) were grown in wells of a 96-well microtiter plate. Culture supernatants were removed and transferred to another microplate that contained cultures of either the MphR mutant E7-RBS or the wild-type biosensor. Fluorescence analysis revealed the unequivocal detection of only those wells containing the producing strain, and demonstrated the superior dynamic range of the engineered vs. wild-type biosensor (
(185) A similar method using biosensor strains immobilized on agar plates reveals the sensitivity of the engineered biosensor and demonstrates the ability to screen culture collection supernatants in high-throughput via agar plates (
Example 12
Growth Selection for Erythromycin Producing Strains
(186) Wild-type (WT) MphR was used to control expression of the chloramphenicol (Cm) resistance gene via the plasmid pMLCmR (
(187) A similar trend was observed when the engineered MphR E7-M9C4 was used in place of the wild-type MphR. However, using this clarithromycin-selective MphR variant, at 5 μM polyketide, colonies grew when clarithromycin was provided but not in the presence of erythromycin, thus highlighting the improved sensitivity of this mutant, in comparison to the wild-type biosensor (
(188) TABLE-US-00015 SEQUENCES Provided herein is the gene sequence of the wild- type MphR gene: DNA sequence-Wild-type MphR ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 1) Also provided herein is the amino acid sequence of the wild-type MphR protein: Amino acid sequence-Wild-type MphR MPRPKLKSDDEVLEAATVVLKRCGPIEFTLSGVAKEVGLSRAALIQRFTN RDTLLVRMMERGVEQVRHYLNAIPIGAGPQGLWEFLQVLVRSMNTRNDFS VNYLISWYELQVPELRTLAIQRNRAVVEGIRKRLPPGAPAAAELLLHSVI AGATMQWAVDPDGELADHVLAQIAAILCLMFPEHDDFQLLQAHA (SEQ ID NO: 2) Provided herein are the gene sequences of the MphR mutations (see Table 11) (mutated nucleotides are underlined) (the sequences directly below only contain the coding sequences; for additional sequence upstream of ATG, see SEQ ID NO: 28-57). epA3 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATATGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 3) epE7 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTTAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCATTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 4) epH4 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCATTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAATGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCTTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 5) QCMS3D6 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAG GGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GGATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGA CTGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCAT CGCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTG ATCATGTGCTGGCTCAGATCGCTTGCCATCCTGTGTTTTAATGTTTCCCG AACAcGAcGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 6) QCMS3F8 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCGC GGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGAGTGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 7) QCMS5B4 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCGG TGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGATGGTTCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC AcGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 8) QCMS5D7 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCGC TGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGGAGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 9) D3 (pikB1) ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTTCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 10) YCA11 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGAGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCTGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG ACATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 11) Nbn.YCG11 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGTTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 12) NbnD11 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGACTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC CCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCTCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 13) NbnE1 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATTGAGTTCACGCTCAGCGGAGTAT CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCAGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 14) NbnG7 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC TGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 15) M2D6 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTTCTCGAGGCCACCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGTGGAGTGG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTAGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGATGAAGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 16) M2D7 ATGCCCCGCCTCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTTGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACGTGCGTAA (SEQ ID NO: 17) C9 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAT CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACAATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAATTCCTCCAGGCACATGCGTAA (SEQ ID NO: 18) V66P ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGCCACG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 19) V66R ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGAGGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 20) V66G ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGGACG GGCATTACCTGAATGCGATACCGATAGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 21) V66I ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGATCCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 22) V66D ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGACCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 23) M1B10 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGGCTCTCCCGCGCAGCGTTAATCCAGCGCTTCATCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGTTCGTTCGGAGCATGAACACTCGCAACAACTTCTCG GTGAACTATCTCATCTCCTGGTACGATCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGCGGAACCGCGCGGTGGTGGAGGGGATCCGCAAGCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC GCTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC ACGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 24) M9C4 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGACTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGACTAACCGCGCGGTGGTGGAGGGGATCCGCAATCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC ACTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC AAGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 58) E7_M9C4 ATGCCCCGCCCCAAGCTCAAGTCCGATGACGAGGTACTCGAGGCCGCCAC CGTAGTGCTGAAGCGTTGCGGTCCCATAGAGTTCACGCTCAGCGGAGTAG CAAAGGAGGTGGGACTCTCCCGCGCAGCGTTAATCCAGCGCTTCACCAAC CGCGATACGCTGCTGGTGAGGATGATGGAGCGCGGCGTCGAGCAGGTGCG GCATTACCTGAATGCGATACCGATAGGCGCAGGGCCGCAAGGGCTCTGGG AATTTTTGCAGGTGCTCGTTCGGAGCATGAACACTCGCAACGACTTCTCG GTGAACTATCTCATCTCCTGGTACGAGCTCCAGGTGCCGGAGCTACGCAC GCTTGCGATCCAGACTAACCGCGCGGTGGTGGAGGGGATCCGCAATCGAC TGCCCCCAGGTGCTCCTGCGGCAGCTGAGTTGCTCCTGCACTCGGTCATC ACTGGCGCGACGATGCAGTGGGCCGTCGATCCGGATGGTGAGCTAGCTGA TCATGTGCTGGCTCAGATCGCTGCCATCCTGTGTTTAATGTTTCCCGAAC AAGACGATTTCCAACTCCTCCAGGCACATGCGTAA (SEQ ID NO: 59)
(189) Provided herein are the nucleic acid sequences for the plasmid vectors disclosed above:
(190) TABLE-US-00016 Plasmid pMLGFP: LOCUS pMLGFP 3957bp DNA circular SOURCE ORGANISM COMMENT This file is created by Vector NTI http://www.informaxinc.com/ COMMENT VNTDATE|493119689| COMMENT VNTDBDATE|508971571| COMMENT VNTNAME|pMLGFP| COMMENT VNTAUTHORNAME|zh| FEATURES Location/Qualifiers misc_feature 1796..1953 /vntifkey=“21” /label=Terminator CDS 2233..3093 /vntifkey=“4” /label=Amp rep_origin 3238..3911 /vntifkey=“33” /label=pBR322\ori CDS complement(103..687) /vntifkey=“4” /label=MphR promoter complement(716..752) /vntifkey=“30” /label=PlacIQ RBS 697..702 /vntifkey=“32” /label=RBS promoter 759..842 /vntifkey=“30” /label=lac\promoter promoter 843..880 /vntifkey=“30” /label=PmphR CDS 901..1617 /vntifkey=“4” /label=GFP RBS 887..892 /vntifkey=“32” /label=RBS BASE COUNT 1017 a 972 c 992 g 976 t ORIGIN
(191) TABLE-US-00017 (SEQ ID NO: 25) 1 tctagtgtac agtgatcaag acttcgatac caccgaccgt accggtacta atcgacgacg 61 gtcgtgttcg tcgcctgccg cagggactct gcacacctcc gtttacgcat gtgcctggag 121 gagttggaaa tcgtcgtgtt cgggaaacat taaacacagg atggcagcga tctgagccag 181 cacatgatca gctagctcac catccggatc gacggcccac tgcatcgtcg cgccagcgat 241 gaccgagtgc aggagcaact cagctgccgc aggagcacct gggggcagtc gcttgcggat 301 cccctccacc accgcgcggt tccgctggat cgcaagcgtg cgtagctccg gcacctggag 361 ctcgtaccag gagatgagat agttcaccga gaagtcgttg cgagtgttca tgctccgaac 421 gagcacctgc aaaaattccc agagcccttg cggccctgcg cctatcggta tcgcattcag 481 gtaatgccgc acctgctcga cgccgcgctc catcatcctc accagcagcg tatcgcggtt 541 ggtgaagcgc tggattaacg ctgcgcggga gagccccacc tcctttgcta ctccgctgag 601 cgtgaactct atgggaccgc aacgcttcag cactacggtg gcggcctcga gtacctcgtc 661 atcggacttg agcttggggc ggggcatcag tgttcacctt ctgtatgggt tggggggcgc 721 tatcatgcca taccgcgaaa ggttttgcac catctagagc gcaacgcaat taatgtgagt 781 tagctcactc attaggcacc ccaggcttta cactttatgc ttccggctcg tatgttgtgt 841 gggattgaat ataaccgacg tgactgttac atttaggtgg gctaacagga ggaaactagt 901 atgagtaaag gagaagaact tttcactgga gttgtcccaa ttcttgttga attagatggt 961 gatgttaatg ggcacaaatt ttctgtcagt ggagagggtg aaggtgatgc aacatacgga 1021 aaacttaccc ttaaatttat ttgcactact ggaaaactac ctgttccatg gccaacactt 1081 gtcactactt tctcttatgg tgttcaatgc ttttcccgtt atccggatca tatgaaacgg 1141 catgactttt tcaagagtgc catgcccgaa ggttatgtac aggaacgcac tatatctttc 1201 aaagatgacg ggaactacaa gacgcgtgct gaagtcaagt ttgaaggtga tacccttgtt 1261 aatcgtatcg agttaaaagg tattgatttt aaagaagatg gaaacattct cggacacaaa 1321 ctcgagtaca actataactc acacaatgta tacatcacgg cagacaaaca aaagaatgga 1381 atcaaagcta acttcaaaat tcgccacaac attgaagatg gatccgttca actagcagac 1441 cattatcaac aaaatactcc aattggcgat ggccctgtcc ttttaccaga caaccattac 1501 ctgtcgacac aatctgccct ttcgaaagat cccaacgaaa agcgtgacca catggtcctt 1561 cttgagtttg taactgctgc tgggattaca catggcatgg atgagctcta caaataagct 1621 tgggcccgaa caaaaactca tctcagaaga ggatctgaat agcgccgtcg accatcatca 1681 tcatcatcat tgagtttaaa cggtctccag cttggctgtt ttggcggatg agagaagatt 1741 ttcagcctga tacagattaa atcagaacgc agaagcggtc tgataaaaca gaatttgcct 1801 ggcggcagta gcgcggtggt cccacctgac cccatgccga actcagaagt gaaacgccgt 1861 agcgccgatg gtagtgtggg gtctccccat gcgagagtag ggaactgcca ggcatcaaat 1921 aaaacgaaag gctcagtcga aagactgggc ctttcgtttt atctgttgtt tgtcggtgaa 1981 cgctctcctg agtaggacaa atccgccggg agcggatttg aacgttgcga agcaacggcc 2041 cggagggtgg cgggcaggac gcccgccata aactgccagg catcaaatta agcagaaggc 2101 catcctgacg gatggccttt ttgcgtttct acaaactctt tttgtttatt tttctaaata 2161 cattcaaata tgtatccgct catgagacaa taaccctgat aaatgcttca ataatattga 2221 aaaaggaaga gtatgagtat tcaacatttc cgtgtcgccc ttattccctt ttttgcggca 2281 ttttgccttc ctgtttttgc tcacccagaa acgctggtga aagtaaaaga tgctgaagat 2341 cagttgggtg cacgagtggg ttacatcgaa ctggatctca acagcggtaa gatccttgag 2401 agttttcgcc ccgaagaacg ttttccaatg atgagcactt ttaaagttct gctatgtggc 2461 gcggtattat cccgtgttga cgccgggcaa gagcaactcg gtcgccgcat acactattct 2521 cagaatgact tggttgagta ctcaccagtc acagaaaagc atcttacgga tggcatgaca 2581 gtaagagaat tatgcagtgc tgccataacc atgagtgata acactgcggc caacttactt 2641 ctgacaacga tcggaggacc gaaggagcta accgcttttt tgcacaacat gggggatcat 2701 gtaactcgcc ttgatcgttg ggaaccggag ctgaatgaag ccataccaaa cgacgagcgt 2761 gacaccacga tgcctgtagc aatggcaaca acgttgcgca aactattaac tggcgaacta 2821 cttactctag cttcccggca acaattaata gactggatgg aggcggataa agttgcagga 2881 ccacttctgc gctcggccct tccggctggc tggtttattg ctgataaatc tggagccggt 2941 gagcgtgggt ctcgcggtat cattgcagca ctggggccag atggtaagcc ctcccgtatc 3001 gtagttatct acacgacggg gagtcaggca actatggatg aacgaaatag acagatcgct 3061 gagataggtg cctcactgat taagcattgg taactgtcag accaagttta ctcatatata 3121 ctttagattg atttaaaact tcatttttaa tttaaaagga tctaggtgaa gatccttttt 3181 gataatctca tgaccaaaat cccttaacgt gagttttcgt tccactgagc gtcagacccc 3241 gtagaaaaga tcaaaggatc ttcttgagat cctttttttc tgcgcgtaat ctgctgcttg 3301 caaacaaaaa aaccaccgct accagcggtg gtttgtttgc cggatcaaga gctaccaact 3361 ctttttccga aggtaactgg cttcagcaga gcgcagatac caaatactgt ccttctagtg 3421 tagccgtagt taggccacca cttcaagaac tctgtagcac cgcctacata cctcgctctg 3481 ctaatcctgt taccagtggc tgctgccagt ggcgataagt cgtgtcttac cgggttggac 3541 tcaagacgat agttaccgga taaggcgcag cggtcgggct gaacgggggg ttcgtgcaca 3601 cagcccagct tggagcgaac gacctacacc gaactgagat acctacagcg tgagctatga 3661 gaaagcgcca cgcttcccga agggagaaag gcggacaggt atccggtaag cggcagggtc 3721 ggaacaggag agcgcacgag ggagcttcca gggggaaacg cctggtatct ttatagtcct 3781 gtcgggtttc gccacctctg acttgagcgt cgatttttgt gatgctcgtc aggggggcgg 3841 agcctatgga aaaacgccag caacgcggcc tttttacggt tcctggcctt ttgctggcct 3901 tttgctcaca tgttctttcc tgcgttatcc cctgattctg tggataaccg tattacc
(192) TABLE-US-00018 Plasmid pJZ12: LOCUS pJZ12 5131 bp DNA circular SOURCE ORGANISM COMMENT This file is created by Vector NTI http://www.informaxinc.com/ COMMENT VNTDATE|493491327| COMMENT VNTDBDATE|508971571| COMMENT VNTNAME|pJZ12| COMMENT VNTAUTHORNAME|zh| FEATURES Location/Qualifiers CDS 582..1772 /vntifkey=“4” /label=TetR rep_origin 4713..412 /vntifkey=“33” /label=rep(p15A) CDS 2945..3850 /vntifkey=“4” /label=mphA CDS 3847..4649 /vntifkey=“4” /label=mrx\incomplete\CDS BASE COUNT 980 a 1521 c 1515 c 11151 t ORIGIN
(193) TABLE-US-00019 (SEQ ID NO: 26) 1 tcattccgct gttatggccg cgtttgtctc attccacgcc tgacactcag ttccgggtag 61 gcagttcgct ccaagctgga ctgtatgcac gaaccccccg ttcagtccga ccgctgcgcc 121 ttatccggta actatcgtct tgagtccaac ccggaaagac atgcaaaagc accactggca 181 gcagccactg gtaattgatt tagaggagtt agtcttgaag tcatgcgccg gttaaggcta 241 aactgaaagg acaagttttg gtgactgcgc tcctccaagc cagttacctc ggttcaaaga 301 gttggtagct cagagaacct tcgaaaaacc gccctgcaag geggtttttt cgttttcaga 361 gcaagagatt acgcgcagac caaaacgatc tcaagaagat catcttatta atcagataaa 421 atatttctag atttcagtgc aatttatctc ttcaaatgta gcacctgaag tcagccccat 481 acgatataag ttgtaattct catgtttgac agcttatcat cgataagctt taatgcggta 541 gtttatcaca gttaaattgc taacgcagtc aggcaccgtg tatgaaatct aacaatgcgc 601 tcatcgtcat cctcggcacc gtcaccctgg atgctgtagg cataggcttg gttatgccgg 661 tactgccggg cctcttgcgg gatatcgtcc attccgacag catcgccagt cactatggcg 721 tgctgctagc gctatatgcg ttgatgcaat ttctatgcgc acccgttctc ggagcactgt 781 ccgaccgctt tggccgccgc ccagtcctgc tcgcttcgct acttggagcc actatcgact 841 acgcgatcat ggcgaccaca cccgtcctgt ggatcctcta cgccggacgc atcgtggccg 901 gcatcaccgg cgccacaggt gcggttgctg gcgcctatat cgccgacatc accgatgggg 961 aagatcgggc tcgccacttc gggctcatga gcgcttgttt cggcgtgggt atggtggcag 1021 gccccgtggc cgggggactg ttgggcgcca tctccttgca tgcaccattc cttgcggcgg 1081 cggtgctcaa cggcctcaac ctactactgg gctgcttcct aatgcaggag tcgcataagg 1141 gagagcgtcg accgatgccc ttgagagcct tcaacccagt cagctccttc cggtgggcgc 1201 ggggcatgac tatcgtcgcc gcacttatga ctgtcttctt tatcatgcaa ctcgtaggac 1261 aggtgccggc agcgctctgg gtcattttcg gcgaggaccg ctttcgctgg agcgcgacga 1321 tgatcggcct gtcgcttgcg gtattcggaa tcttgcacgc cctcgctcaa gccttcgtca 1381 ctggtcccgc caccaaacgt ttcggcgaga agcaggccat tatcgccggc atggcggccg 1441 acgcgctggg ctacgtcttg ctggcgttcg cgacgcgagg ctggatggcc ttccccatta 1501 tgattcttct cgcttccggc ggcatcggga tgcccgcgtt gcaggccatg ctgtccaggc 1561 aggtagatga cgaccatcag ggacagcttc aaggatcgct cgcggctctt accagcctaa 1621 cttcgatcac tggaccgctg atcgtcacgg cgatttatgc cgcctcggcg agcacatgga 1681 acgggttggc atggattgta ggcgccgccc tataccttgt ctgcctcccc gcgttgcgtc 1741 gcggtgcatg gagccgggcc acctcgacct gaatggaagc cggcggcacc tcgctaacgg 1801 attcaccact ccaagaattg gagccaatca attcttgcgg agaactgtga atgcgcaaac 1861 caacccttgg cagaacatat ccatcgcgtc cgccatctcc agcagccgca cgcggcgcat 1921 ctcgggcagc gttgggtcct ggccacgggt gcgcatgatc gtgctcctgt cgttgaggac 1981 ccggctaggc tggcggggtt gccttactgg ttagcagaat gaatcaccga tacgcgagcg 2041 aacgtgaagc gactgctgct gcaaaacgtc tgcgacctga gcaacaacat gaatggtctt 2101 cggtttccgt gtttcgtaaa gtctggaaac gcggaagtcc cctacgtgct gctgaagttg 2161 cccgcaacag agagtggaac cggtacccgg ggatcctcta gagtcgacct gcaggagatg 2221 ctggctgaac gcggagtgaa tgtcgatcac tccacgattt accgctgggt tcagcgttat 2281 gcgcctgaaa tggaaaaacg gctgcgctgg tactggcgta acccttccga tctttgcccg 2341 tggcacatgg atgaaaccta cgtgaaggtc aatggccgct gggcgtatct gtaccgggcc 2401 gtcgacagcc ggggccgcac tgtcgatttt tatctctcct cccgtcgtaa cagcaaagct 2461 gcataccggt ttctgggtaa aatcctcaac aacgtgaaga agtggcagat cccgcgattc 2521 atcaacacgg ataaagcgcc cgcctatggt cgcgcgcttg ctctgctcaa acgcgaaggc 2581 cggtgcccgt ctgacgttga acaccgacag attaagtacc ggaacaacgt gattgaatgc 2641 gatcatggca aactgaaacg gataatcggc gccacgctgg gatttaaatc catgaagacg 2701 gcttacgcca ccatcaaagg tattgaggtg atgcgtgcac tacgcaaagg ccaggcctca 2761 gcattttatt atggtgatcc cctgggcgaa atgcgcctgg taagcagagt ttttgaaatg 2821 taaggccttt gaataagaca aaaggctgcc tcatcgctaa ctttgcaaca gtgccggatt 2881 gaatataacc gacgtgactg ttacatttag gtggctaaac ccgtcaagcc ctcaggagtg 2941 aatcatgacc gtagtcacga ccgccgatac ctcccaactg tacgcacttg cagcccgaca 3001 tgggctcaag ctccatggcc cgctgactgt caatgagctt gggctcgact ataggatcgt 3061 gatcgccacc gtcgacgatg gacgtcggtg ggtgctgcgc atcccgcgcc gagccgaggt 3121 aagcgcgaag gtcgaaccag aggcgcgggt gctggcaatg ctcaagaatc gcctgccgtt 3181 cgcggtgccg gactggcgcg tggccaacgc cgagctcgtt gcctatccca tgctcgaaga 3241 ctcgactgcg atggtcatcc agcctggttc gtccacgccc gactgggtcg tgccgcagga 3301 ctcggaggtc ttcgcggaga gcttcgcgac cgcgctcgcc gccctgcatg ccgtccccat 3361 ttccgccgcc gtggatgcgg ggatgctcat ccgtacaccg acgcaggccc gtcagaaggt 3421 ggccgacgac gttgaccgcg tccgacgcga gttcgtggtg aacgacaagc gcctccaccg 3481 gtggcagcgc tggctcgacg acgattcgtc gtggccagat ttctccgtgg tggtgcatgg 3541 cgatctctac gtgggccatg tgctcatcga caacacggag cgcgtcagcg ggatgatcga 3601 ctggagcgag gcccgcgttg atgaccctgc catcgacatg gccgcgcacc ttatggtctt 3661 tggtgaagag gggctcgcga agctcctcct cacgtatgaa gcggccggtg gccgggtgtg 3721 gccgcggctc gcccaccaca tcgcggagcg ccttgcgttc ggggcggtca cctacgcact 3781 cttcgccctc gactcgggta acgaagagta cctcgctgcg gcgaaggcgc agctcgccgc 3841 agcggaatga gcgaacgtcg atatagcccg ctcgcgacgc tgttcgcggc gacctttctc 3901 ttccggatcg gcaacgcggt ggcggccctc gcgcttccat ggttcgtcct gtctcataca 3961 aagagcgcgg cctgggcggg cgccacggcc gctagcagcg tcatcgcgac catcatcggc 4021 gcgtgggttg gtggtggcct cgtcgatcgg ttcgggcgcg cgcccgtcgc attgatctcg 4081 ggtgtggtgg gcggcgtggc catggcgagc atcccactgc tcgatgccgt tggcgccctc 4141 tcgaacactg ggctgatcgc ttgcgtggtg ctcggtgccg cgttcgacgc acccggtatg 4201 gccgcgcagg acagtgagct gcccaaactc ggccacgtcg ccgggctctc cgttgagcgc 4261 gtctcgtcac tgaaagcggt gatcgggaac gtcgcgattc taggtggccc ggcccttggg 4321 ggggccgcaa tcggcctgct tggcgctgcg ccaacgctcg ggctgacggc gttctgctcc 4381 gtccttgcag gtctgctcgg cgcgtgggtg cttcccgcgc gtgccgctcg gacgatgacc 4441 acgacggcga ctctctccat gcgcgccggc gtcgcttttc tctggagcga acccctgctg 4501 cgccctctct ttggtatagt gatgatcttc gtgggcatcg ttggcgccaa cggcagcgtc 4561 atcatgcctg cgctgtttgt agatgcagga cgccaagtag cagagctcgg gctgttctcc 4621 tcaatgatgg gggctggtgg tctccttggc tgtccctcct gttcagctac tgacggggtg 4681 gtgcgtaacg gcaaaagcac cgccggacat cagcgctagc ggagtgtata ctggcttact 4741 atgttggcac tgatgagggt gtcagtgaag tgcttcatgt ggcaggagaa aaaaggctgc 4801 accggtgcgt cagcagaata tgtgatacag gatatattcc gcttcctcgc tcactgactc 4861 gctacgctcg gtcgttcgac tgcggcgagc ggaaatggct tacgaacggg gcggagattt 4921 cctggaagat gccaggaaga tacttaacag ggaagtgaga gggccgcggc aaagccgttt 4981 ttccataggc tccgcccccc tgacaagcat cacgaaatct gacgctcaaa tcagtggtgg 5041 cgaaacccga caggactata aagataccag gcgtttcccc ctggcggctc cctcgtgcgc 5101 tctcctgttc ctgcctttcg gtttaccggt g
DNA Sequences with Upstream Nucleotide Sequences Mutated nucleotides are underlined RBS region is shown bold Start codon is shown boxed
(194) TABLE-US-00020 WT (SEQ ID NO: 28)
(195) In some embodiments, the MphR gene sequence may be codon optimized, without changing the resulting polypeptide sequence. In some embodiments, the codon optimization includes replacing at least one, or more than one, or a significant number, of codons.
(196) In some embodiments, the MphR gene sequence is substantially identical to the wild-type MphR sequence (SEQ ID NO:1). In some embodiments, the MphR gene is about 60% identical, preferably 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher, over a specified region when compared and aligned for maximum correspondence with the wild-type sequence.
(197) In some embodiments, the MphR gene sequence is substantially identical to the wild-type MphR sequence (SEQ ID NO:28) (which includes gene sequences upstream of the start codon). In some embodiments, the MphR gene is about 60% identical, preferably 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher, over a specified region when compared and aligned for maximum correspondence with the wild-type sequence.
(198) Throughout this application, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this pertains. The references disclosed are also individually and specifically incorporated by reference herein for the material contained in them that is discussed in the sentence in which the reference is relied upon.
(199) Those skilled in the art will appreciate that numerous changes and modifications can be made to the preferred embodiments of the invention and that such changes and modifications can be made without departing from the spirit of the invention. It is, therefore, intended that the appended claims cover all such equivalent variations as fall within the true spirit and scope of the invention.