|Title||A Noncanonical Function of Sortase Enables Site-Specific Conjugation of Small Molecules to Lysine Residues in Proteins|
|Publication Type||Journal Article|
|Year of Publication||2015|
|Authors||Bellucci, JJ, Bhattacharyya, J, Chilkoti, A|
|Journal||Angewandte Chemie International Edition|
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.
|Short Title||Angew. Chem. Int. Ed.|