Cysteine reactive groups are a mainstay in the design of covalent drugs and probe molecules, yet only a handful of electrophiles are routinely used to target this amino acid. Here, we report the development of scalable thiol reactivity (STRP), a method which enables the facile interrogation of large chemical libraries for intrinsic reactivity with cysteine. High throughput screening using STRP identified the azetidinyl oxadiazole as a moiety that selectively reacts with cysteine through a ring opening-based mechanism, capable of covalently engaging cysteine residues broadly across the human proteome. We show the utility of this reactive group with the discovery of an azetidinyl oxadiazole containing a small molecule that augments the catalytic activity of the deubiquitinase UCHL1 in vitro and in cells by covalently modifying a cysteine distal to its enzymatic active site. This study adds a novel cysteine targeting group to the electrophilic lexicon and provides robust methodology to rapidly surveil libraries for reactivity with cysteine.

中文翻译：

---

可扩展的巯基反应性分析将氮杂二唑确定为靶向半胱氨酸的亲电试剂


半胱氨酸反应性基团是共价药物和探针分子设计中的支柱，但通常只有少数亲电试剂用于靶向该氨基酸。在这里，我们报告了可扩展巯基反应性 （STRP） 的发展，这种方法能够轻松查询大型化学库与半胱氨酸的内在反应性。使用 STRP 进行高通量筛选，将氮杂丁基噁二唑鉴定为通过基于开环机制选择性地与半胱氨酸反应的部分，能够在人蛋白质组中广泛共价接合半胱氨酸残基。我们通过发现一种含有小分子的氮杂酰基恶二唑来展示该反应基团的效用，该小分子通过共价修饰其酶活性位点远端的半胱氨酸来增强体外和细胞中去泛素酶 UCHL1 的催化活性。本研究在亲电词典中添加了一个新的半胱氨酸靶向基团，并提供了快速监测文库与半胱氨酸反应性的可靠方法。