A noncanonical function of sortase enables site-specific conjugation of small molecules to lysine residues in proteins.

ABSTRACT: We provide the first demonstration that isopeptide ligation, a noncanonical activity of the enzyme sortase?A, can be used to modify recombinant proteins. This reaction was used in?vitro to conjugate small molecules to a peptide, an engineered targeting protein, and a full-length monoclonal antibody with an exquisite level of control over the site of conjugation. Attachment to the protein substrate occurred exclusively through isopeptide bonds at a lysine ?-amino group within a specific amino acid sequence. This reaction allows more than one molecule to be site-specifically conjugated to a protein at internal sites, thereby overcoming significant limitations of the canonical native peptide ligation reaction catalyzed by sortase?A. Our method provides a unique chemical ligation procedure that is orthogonal to existing methods, supplying a new method to site-specifically modify lysine residues that will be a valuable addition to the protein conjugation toolbox.

SUBMITTER: Bellucci JJ 

PROVIDER: S-EPMC4314310 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature