Abstract: Chemical cross-linking mass spectrometry in combination with X-ray crystallography, NMR or cryoelectron microscopy have been used extensively by researchers to obtain high resolution protein structures and interactome. Currently available cross-linker reagents target limited repertoire of amino acid residues (Lys, Glu, Asp and Cys). This paper reports a heterobifunctional cross-linker containing a highly reactive N-hydroxysulfosuccinimide that reacts rapidly with Lys and leaving the less reactive group of sulfonyl fluoride to react with weakly nucleophilic sidechains (Ser, Thr, His and Tyr) via proximity-enhanced sulfur-fluoride exchange reaction. Proteins with known structure subjected to this cross-linker yielded cross-linking sites undetectable with existing reagents and are agreeable by crystal structures. This methodology is also capable of detecting transient and weak protein interactions when combined with genetically encoded chemical cross-linking.
Citation: Bing Yang, Haifan Wu, Paul D. Schnier, Yangsheng Liu, Jun Liu, Nanxi Wang, Willian F. DeGrado, and Lei Wang.Proximity-enhanced SuFEx chemical cross-linker for specific and multitargeting cross-linking mass spectrometry.PNAS(2018) 115, 44, 11162-11167