Volume57, Issue22
May 28, 2018
Pages 6459-6463
Issue Online
22 May 2018
Version of Record online:
26 April 2018
Accepted manuscript online:
25 March 2018
Manuscript revised:
07 March 2018
Dr. Chi Zhang Dr. Peng Dai Dr. Alexander A. Vinogradov Dr. Zachary P. Gates Prof. Dr. Bradley L. Pentelute
We report a site‐selective cysteine–cyclooctyne conjugation reaction between a seven‐residue peptide tag (DBCO‐tag, Leu‐Cys‐Tyr‐Pro‐Trp‐Val‐Tyr) at the N or C terminus of a peptide or protein and various aza‐dibenzocyclooctyne (DBCO) reagents. Compared to a cysteine peptide control, the DBCO‐tag increases the rate of the thiol–yne reaction 220‐fold, thereby enabling selective conjugation of DBCO‐tag to DBCO‐linked fluorescent probes, affinity tags, and cytotoxic drug molecules. Fusion of DBCO‐tag with the protein of interest enables regioselective cysteine modification on proteins that contain multiple endogenous cysteines; these examples include green fluorescent protein and the antibody trastuzumab. This study demonstrates that short peptide tags can aid in accelerating bond‐forming reactions that are often slow to non‐existent in water.