Reversible formation of sulfenic acid from cysteinyl thiols in proteins, a post-translational modification termed protein sulfenylation, has emerged as a potential mechanism for protein functions. However, the substrates and specific sites of sulfenylation in thiol proteome remain largely unknown, mainly because of the low abundance and inherent liability of this transient modification, as well as the difficulty of selective capture of sulfenyl peptides for analysis. Here we utilized a bioorthogonal dimedone-based probe, DYn-2, for labeling, capture by Click chemistry, and identification of protein sulfenylation by liquid chromatography-tandem mass spectrometry. We report the first global survey of site-specific protein sulfenylation in human tumor cell lines.  Captured sulfenyl peptides were analyzed on a high resolution Thermo Orbitrap Elite instrument.  We identified >100 cysteine sulfenylation sites on >60 proteins. Preliminary inventories include, in addition to regulators of cellular redox homeostasis, proteins involved in diverse processes, including intermediary metabolism, cytoskeleton, RNA splicing, and nuclear transport. This approach should enable targeted, quantitative assessment of protein sulfenylation as a putative regulator of cellular functions.  Supported by NIH grant U24CA159988.

Site-specific mapping of protein sulfenylation

246th National Meeting (2013)

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