Abstract: Disclosed herein is pyrroline-carboxy-lysine (PCL), a pyrrolysine analogue, which is a natural, biosynthetically generated amino acid, and methods for biosynthetically generating PCL. Also disclosed herein are proteins, polypeptides and peptides that have PCL incorporated therein and methods for incorporating PCL into such proteins, polypeptides and peptides. Also disclosed herein is the site-specific derivatization of proteins, polypeptides and peptides having PCL or pyrrolysine incorporated therein. Also disclosed herein is the crosslinking of proteins, polypeptides and peptides having PCL or pyrrolysine incorporated therein.

Abstract: The invention relates to orthogonal pairs of tRNAs and aminoacyl-tRNA synthetases that can incorporate unnatural amino acids that comprise a 1,2 aminothiol group into polypeptides. The invention provides translation systems in which polypeptides comprising unnatural amino acids that comprise a 1,2 aminothiol group can be produced. The invention also provides methods for producing polypeptides containing unnatural amino acids that comprise a 1,2 aminothiol group. Also provided by the invention are compositions comprising orthogonal aminoacyl-tRNA synthetases that preferentially aminoacylate a cognate orthogonal tRNA with unnatural amino acids that comprise a 1,2 aminothiol group. The invention provides methods for the synthesis of the unnatural amino acid 2-amino-3-(4-(2-amino-3-mercaptopropan-amido)phenyl)-propanoic acid.

Abstract: The present invention comprises methods and compositions for producing and/or enhancing an immunological response in a subject against a target moiety such as a disease-related moiety by administration of an antigenic version of the target moiety having one or more unnatural amino acid and/or by administration of an antibody against a version of a target moiety having one or more unnatural amino acid which antibody is cross reactive with the natural target moiety.

Abstract: The present invention comprises methods and compositions for producing and/or enhancing an immunological response in a subject against a target moiety such as a disease-related moiety by administration of an antigenic version of the target moiety having one or more unnatural amino acid and/or by administration of an antibody against a version of a target moiety having one or more unnatural amino acid which antibody is cross reactive with the natural target moiety.