Department of Pathology and Laboratory Medicine, Robert Larner M.D., College of Medicine, University of Vermont, Burlington, VT, USA.
Department of Environmental Health Sciences and Molecular Toxicology, Tohoku University Graduate School of Medicine, Sendai, Japan.
Redox Biol. 2018 Apr;14:379-385. doi: 10.1016/j.redox.2017.10.006. Epub 2017 Oct 9.
The reversible oxidation of protein cysteine residues (Cys-SH) is a key reaction in cellular redox signaling involving initial formation of sulfenic acids (Cys-SOH), which are commonly detected using selective dimedone-based probes. Here, we report that significant portions of dimedone-tagged proteins are susceptible to cleavage by DTT reflecting the presence of perthiosulfenic acid species (Cys-SSOH) due to similar oxidation of hydropersulfides (Cys-SSH), since Cys-S-dimedone adducts are stable toward DTT. Combined studies using molecular modeling, mass spectrometry, and cell-based experiments indicate that Cys-SSH are readily oxidized to Cys-SSOH, which forms stable adducts with dimedone-based probes. We additionally confirm the presence of Cys-SSH within protein tyrosine kinases such as EGFR, and their apparent oxidation to Cys-SSOH in response NADPH oxidase activation, suggesting that such Cys-SSH oxidation may represent a novel, as yet uncharacterized, event in redox-based signaling.
蛋白质半胱氨酸残基（Cys-SH）的可还原氧化是细胞氧化还原信号转导中的关键反应，涉及亚磺酸（Cys-SOH）的初始形成，通常使用选择性二酮基化合物探针进行检测。在这里，我们报告说，由于类似的氢过硫化物（Cys-SSH）氧化，二酮基标记的蛋白质的很大一部分容易受到 DTT 的切割，反映出存在过硫代亚磺酸（Cys-SSOH）物种，因为 Cys-S-二酮基加合物对 DTT 稳定。使用分子建模、质谱和基于细胞的实验进行的综合研究表明，Cys-SSH 很容易被氧化为 Cys-SSOH，其与基于二酮基的探针形成稳定的加合物。我们还在表皮生长因子受体（EGFR）等蛋白酪氨酸激酶中证实了 Cys-SSH 的存在，并且它们在 NADPH 氧化酶激活时明显被氧化为 Cys-SSOH，这表明这种 Cys-SSH 氧化可能代表氧化还原信号转导中的一种新的、尚未表征的事件。
