The invention relates generally to methods of producing a protein comprising a first unnatural amino acid (UAA) and a second, different UAA, and proteins comprising a first UAA and a second, different UAA.

The present invention provides a recombinant cell for producing para-nitro-L-phenylalanine (pN-Phe). The recombinant cell comprises heterologous genes encoding heterologous enzymes. The recombinant cell expresses the heterologous enzymes and contains a native metabolite. The native metabolite is converted to the pN-Phe in the recombinant cell. The biosynthesized pN-Phe may be incorporated into a target polypeptide in the recombinant cell without requiring exposure of the recombinant cell to exogenous pN-Phe. A cell culture comprising the recombinant cell is also provided. Further provided is a method of producing pN-Phe by a recombinant cell comprising heterologous genes encoding heterologous enzymes. The method comprises expressing a native metabolite by the recombinant cell, expressing the heterologous enzymes, and converting the native metabolite to the pN-Phe in the recombinant cell. The method may further comprise incorporating the pN-Phe into the target polypeptide in the recombinant cell.

Provided herein are modified amino acids comprising a tetrazine groups according to Formula I: polypeptides, antibodies, payloads and conjugates comprising these modified amino acid residues derived from the modified amino acids, and methods of producing the polypeptides, antibodies, payloads and conjugates comprising the modified amino acid residues. The polypeptides, antibodies, payloads and conjugates are useful in methods of treatment and prevention, methods of detection and methods of diagnosis. ##STR00001##

This invention relates to methods of producing a rare amino acid- or non-natural amino acid-containing protein in a cell free protein synthesis system and kits for use in and for accomplishing same. Specifically, the methods comprise the steps of expressing at least one orthogonal suppressor tRNA (o-tRNA)/aminoacyl-tRNA synthetase (aaRS) pair or derivatives thereof specific for incorporation of a rare amino acid- or non-natural amino acid in an E. coli organism; preparing a lysate of said E. coli organism expressing said orthogonal suppressor tRNA (o-tRNA)/aminoacyl-tRNA synthetase (aaRS) pair; and contacting said lysate with a template DNA containing a mutant gene in which at least one amino acid codon at a given site of the protein-encoding gene has been mutated into an amber or ochre mutation and further providing a cognate rare amino acid or non-natural amino acid and other factors necessary for protein synthesis; wherein protein synthesis occurs following said contact to produce a protein containing said at least one rare amino acid or said non-natural amino acid. Kits for use are described, as well.

An engineered tyrosyl-tRNA synthetase/tRNA pair that co-translationally incorporates O-sulfotyrosine in response to UAG codons in E. coli and mammalian cells is described herein. This platform enables recombinant expression of eukaryotic proteins homogeneously sulfated at chosen sites.

Provided herein are methods for labeling the proteomes of cells, as well as methods for labeling proteins or populations of proteins produced by cells. In some embodiments, the methods comprise introducing variant aminoacyl-tRNA synthetases and noncanonical amino acids into cells. Also provided herein are polynucleotides encoding variant aminoacyl-tRNA synthetases that recognize noncanonical amino acids. The methods and compositions provided herein are useful for, among other things, identifying target cells and identifying biomarkers of interest.

This disclosure provides engineered aminoacyl tRNA synthetases and tRNAs for efficient production of proteins containing non-standard amino acids. These engineered orthogonal tRNA (O-tRNA)/orthogonal aminoacyl tRNA synthetase (O-RS) pairs, i.e., Orthogonal Translation Systems (OTSs) can be used to incorporate a non-standard amino acid in a specific position in a growing polypeptide in response to a selector codon that is recognized by the engineered tRNA.

A method for one of altering and enhancing the stereospecificity of an enzyme comprising introducing a stereospecific editing domain into the enzyme.

Provided herein are modified amino acids comprising a tetrazine groups according to Formula I: polypeptides, antibodies, payloads and conjugates comprising these modified amino acid residues derived from the modified amino acids, and methods of producing the polypeptides, antibodies, payloads and conjugates comprising the modified amino acid residues. The polypeptides, antibodies, payloads and conjugates are useful in methods of treatment and prevention, methods of detection and methods of diagnosis.

##STR00001##

Provided herein are methods for labeling the proteomes of cells, as well as methods for labeling proteins or populations of proteins produced by cells. In some embodiments, the methods comprise introducing variant aminoacyl-tRNA synthetases and noncanonical amino acids into cells. Also provided herein are polynucleotides encoding variant aminoacyl-tRNA synthetases that recognize noncanonical amino acids. The methods and compositions provided herein are useful for, among other things, identifying target cells and identifying biomarkers of interest.