Akter, S. et al. Nat. Chem. Biol. https://doi.org/10.1038/s41589-018-0116-2 (2018).
The amino acid cysteine undergoes many different oxidative post-translational modifications involved both in disease and in the regulation of various biological functions. S-sulfinylation is a particularly elusive modification that has been a biochemical challenge to study, and its biological function has thus remained unresolved. Akter et al. now report a clickable, electrophilic diazene probe called DiaAlk, which allows them to enrich for proteins containing sulfinic acid modifications. The probe facilitates mass-spectrometry-based identification of such modified proteins, or fluorescence-based detection in cells. The researchers used DiaAlk in several applications, including analysis of cysteines in A549 or HeLa cells that had undergone hyperoxidation after the addition of hydrogen peroxide. The approach also enabled them to compare the targets of S-sulfinylation with those of S-sulfenylation, and to identify protein substrates of the cysteine sulfinic acid reductase sulfiredoxin in mouse embryonic fibroblasts.
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Investigating protein thiol chemistry associated with dehydroascorbate, homocysteine and glutathione using mass spectrometry
Rapid Communications in Mass Spectrometry (2020)