Mapping Peptide–Protein Interactions by Amine-Reactive Cleavable Photoaffinity Reagents

Photoaffinity labeling followed by tandem mass spectrometry is an often used strategy to identify protein targets of small-molecule drugs or drug candidates, which, under ideal conditions, enables the identification actual binding site. In case bioactive peptides, however, identifying distinct site hampered because complex fragmentation patterns during spectrometry. We here report development and use small cleavable photoaffinity reagents that allow functionalization peptides for light-induced covalent their targets. Upon cleavage covalently linked peptide drug, a chemical remnant defined remains on bound amino acid, which then unambiguously Applying our approach known peptide–drug/protein pairs with reported crystal structures, such as calmodulin–melittin interaction, we were able validate identified sites based structural models. Overall, represents powerful tool enable specific wide variety in future.