Reactivity of persulfides toward strained bicyclo[6.1.0]nonyne derivatives: relevance to chemical tagging of proteins.

Persulfides are an emerging class of cysteine oxidative post-translational modification. They react with the bioconjugation reagents bicylo[6.1.0]nonynes (BCNs) to engender thioethers and/or disulfides. This new reactivity of BCNs with a biologically important redox-signaling species efficiently interferes with the recent usage of strained cycloalkynes to specifically trap protein sulfenic acids.