A Quantitative Chemoproteomic Platform to Monitor Selenocysteine Reactivity within a Complex Proteome

作者：Bak, Daniel W.^*; Gao, Jinjun; Wang, Chu; Weerapana, Eranthie^*

来源：Cell Chemical Biology, 2018, 25(9): 1157-+.

DOI：10.1016/j.chembiol.2018.05.017

• THIOREDOXIN REDUCTASE
• EXPRESSION PROFILES
• CATHEPSIN-B
• SELENIUM
• CANCER
• SELENOPROTEIN
• GENE
• INHIBITION
• AURANOFIN
• PROLIFERATION

Mammalian selenocysteine (Sec)-containing proteins, selenoproteins, are important to (patho)physiological processes, including redox homeostasis. Sec residues have been recalcitrant to mass spectrometry-based chemoproteomic methods that enrich for reactive cysteine (Cys) residues with electrophilic chemical probes, despite confirmed reactivity of Sec with these electrophiles. Highly abundant Cys peptides likely suppress low-abundant Sec peptides. By exploiting the decreased pK(a) of Sec relative to Cys, we have developed a chemoproteomic platform that relies on low pH (pH 5.75) electrophile labeling, reducing Cys reactivity and enhancing identification of Sec-containing peptides across mouse tissues and cell lines. The utility of this Sec-profiling platform is underscored by evaluation of the selectivity of auranofin, an inhibitor of the selenoprotein, thioredoxin reductase, against both reactive Cys- and Sec-containing proteins. Platform limitations pertain to the non-physiological low-pH conditions that could perturb protein structure and function. Future work necessitates the discovery of Sec-selective electrophiles that function at physiological pH.

• 出版日期2018-9-20
• 单位北京大学