Friday, November 15, 2024

Scalable Thiol Reactivity Profiling Identifies Azetidinyl Oxadiazoles as Cysteine-Targeting Electrophiles

Fereshte Ghorbani, Shaochen You, Gennadii A. Grabovyi, Mannkyu Hong, Garrett Lindsey, Arnab K. Chatterjee, and Michael J. Bollong

Journal of the American Chemical Society 2024

DOI: 10.1021/jacs.4c05711

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.

A covalent inhibitor targeting Cys16 on RhoA in colorectal cancer

Tin-Yan Koo, Jason Ying Ki Li, Nga-Sze Lee, Jintian Chen, Hillary Yui-Yan Yip, Ianto Bosheng Huang, Kai-Yu Ng, Helen H.N. Yan, Suet Yi Leung...