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Updated: May 9, 2026

In Vivo Proximity Biotinylation for Protein Interaction Studies in Paramecium tetraurelia
Published on: September 12, 2025
Adding an unnatural covalent bond to proteins through proximity-enhanced bioreactivity
Zheng Xiang1, Haiyan Ren, Ying S Hu
1The Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, La Jolla, California, USA.
Abstract:
Natural proteins often rely on the disulfide bond to covalently link side chains. Here we genetically introduce a new type of covalent bond into proteins by enabling an unnatural amino acid to react with a proximal cysteine. We demonstrate the utility of this bond for enabling irreversible binding between an affibody and its protein substrate, capturing peptide-protein interactions in mammalian cells, and improving the photon output of fluorescent proteins.
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