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


Journal Article

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.

Full Text

Duke Authors

Cited Authors

  • Bellucci, JJ; Bhattacharyya, J; Chilkoti, A

Published Date

  • January 2015

Published In

Volume / Issue

  • 54 / 2

Start / End Page

  • 441 - 445

PubMed ID

  • 25363491

Pubmed Central ID

  • 25363491

Electronic International Standard Serial Number (EISSN)

  • 1521-3773

International Standard Serial Number (ISSN)

  • 1433-7851

Digital Object Identifier (DOI)

  • 10.1002/anie.201408126


  • eng