Alkyne-A-DSBSO (alkyne-tagged, acid-cleavable disuccinimidyl bissulfoxide) Crosslinker is a homobifunctional, membrane-permeable, enrichable disulfoxide-containing crosslinker for analysis of protein-protein interactions (PPIs) through crosslinking mass spectrometry (XL-MS).
Alkyne-A-DSBSO possesses two N-hydroxysuccinimide (NHS) ester groups for targeting amines, a ∼14 Å spacer length, two symmetrical acid-cleavable C-S bonds, and a central bioorthogonal azide tag. After reacting with lysine (Lys) residues, the alkyne tag permits selective enrichment of crosslinked proteins or peptides with a biotin-conjugated azide probe to enhance their detection. Additionally, the post-cleavage spacer yields tagged peptides for unambiguous identification by collision-induced dissociation in tandem MS.
Alkyne-A-DSBSO Crosslinker has mapped in vivo PPIs for target protein complexes and whole proteomes from living cells. It will also be a useful proteomics tool in the quest for targeting ″undruggable″ protein targets.