The present invention is directed to methods of screening populations of transgenic cells for cells that produce a protein of interest. The methods comprise culturing transgenic cells in culture conditions that include at least one non-natural amino acid (nnAA) in the cell culture medium. The transgenic cells comprise at least one polynucleotide that codes for a fusion protein with a first domain coding for a protein of interest and a second domain coding for a domain that facilitates detection of the transgenic cells that express the protein of interest when the transgenic cell expresses the second domain.

The invention relates to genetic incorporation of 2,3-diamino propionic acid (DAP) into polypeptides, to unnatural amino acids comprising DAP, to a tRNA synthetase for charging tRNA with unnatural amino acids comprising DAP, and to methods of using the resulting polypeptides, for example in capturing substrates and/or intermediates in enzymatic reactions. The invention also relates to compounds of formula (I) or (II): or salts, solvates, tautomers, isomers or mixtures thereof.

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Provided herein are compositions and methods for generating polypeptides using non-natural amino acids (nnAAs) and genetic machinery, wherein the modified polypeptides, such as therapeutic polypeptides, bind to albumin, such as serum albumin. Methods of substituting a non-natural amino acid in a first polypeptide to obtain a modified polypeptide, the nnAA in some instances comprising an albumin targeting group, are disclosed, as are methods for making populations of such modified polypeptides. A therapeutic polypeptide, interleukin-1 receptor antagonist (IL-1RA) is exemplified using the disclosed methods.

Provided herein are compositions and methods for generating polypeptides using non-natural amino acids (nnAAs) and genetic machinery, wherein the modified polypeptides, such as therapeutic polypeptides, bind to albumin, such as serum albumin. Methods of substituting a non-natural amino acid in a first polypeptide to obtain a modified polypeptide, the nnAA in some instances comprising an albumin targeting group, are disclosed, as are methods for making populations of such modified polypeptides. A therapeutic polypeptide, interleukin-1 receptor antagonist (IL-1RA) is exemplified using the disclosed methods.

The present invention relates to the field of pyrrolysyl-tRNA synthetases, their variants and uses thereof. Particularly, the present invention relates to variants (mutants) of parent pyrrolysyl-tRNA synthetases, wherein said variants have pyrrolysyl-tRNA synthetase activity and exhibit altered properties relative to the corresponding parent pyrrolysyl-tRNA synthetase.

Provided herein are novel materials and methods for site-specific incorporation of phosphotyrosines into proteins. The novel methods of the invention encompass the use of a novel aminoacyl tRNA synthetase capable of charging compatible tRNAs with a phosphotyrosine precursor. The phosphotyrosine precursor is then incorporated, site-specifically, into a protein at sites where phosphotyrosine residues are desired. The phosphotyrosine precursors are subsequently treated to convert them into phosphotyrosine residues, yielding proteins with phosphotyrosines at selected sites. The scope of the invention encompasses novel aminoacyl tRNA synthetases, novel phosphotyrosine precursors, and methods of using these materials to create site-specific phosphorylated tyrosine residues in a protein.

The invention relates to a polypeptide comprising an amino acid having a bicyclo[6.1.0]non-4-yn-9-ylmethanol (BCN) group, particularly when said BCN group is present as: a residue of a lysine amino acid. The invention also relates to a method of producing a polypeptide comprising a BCN group, said method comprising genetically incorporating an amino acid comprising a BCN group into a polypeptide. The invention also relates to an amino acid comprising bicyclo[6.1.0]non-4-yn-9-ylmethanol (BCN), particularly and amino acid which is bicyclo[6.1.0]non-4-yn-9-ylmethanol (BCN) lysine. In addition the invention relates to a PylRS tRNA synthetase comprising the mutations Y271M, L274G and C313A.

Provided herein are novel materials and methods for site-specific incorporation of phosphotyrosines into proteins. The novel methods of the invention encompass the use of a novel aminoacyl tRNA synthetase capable of charging compatible tRNAs with a phosphotyrosine precursor. The phosphotyrosine precursor is then incorporated, site-specifically, into a protein at sites where phosphotyrosine residues are desired. The phosphotyrosine precursors are subsequently treated to convert them into phosphotyrosine residues, yielding proteins with phosphotyrosines at selected sites. The scope of the invention encompasses novel aminoacyl tRNA synthetases, novel phosphotyrosine precursors, and methods of using these materials to create site-specific phosphorylated tyrosine residues in a protein.

The disclosure provides amino acid sequence variants of orthogonal aminoacyl-tRNA synthetases (AARSs) having increased activity and selectivity compared to previous AARSs, and methods of producing the same.

Provided are a polypeptide derivative and a preparation method thereof. Specifically, a polypeptide derivative is provided. Experimental results show that the polypeptide derivative has a significantly prolonged half-life while maintaining biological activity. The preparation method of the polypeptide derivative and its use in therapy are also disclosed.