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A Noncanonical Function of Sortase Enables Site‐Specific Conjugation of Small Molecules to Lysine Residues in Proteins
Author(s) -
Bellucci Joseph J.,
Bhattacharyya Jayanta,
Chilkoti Ashutosh
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201408126
Subject(s) - sortase , sortase a , lysine , chemistry , conjugate , peptide , chemical ligation , peptide bond , conjugated system , combinatorial chemistry , small molecule , amino acid , substrate (aquarium) , ligation , stereochemistry , biochemistry , biology , organic chemistry , microbiology and biotechnology , polymer , mathematical analysis , ecology , mathematics , bacterial protein , gene
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 ε‐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.