Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92307, United States.
Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin 10117, Germany.
J Am Chem Soc. 2022 Oct 12;144(40):18688-18699. doi: 10.1021/jacs.2c08964. Epub 2022 Sep 28.
Targeted protein degradation induced by heterobifunctional compounds and molecular glues presents an exciting avenue for chemical probe and drug discovery. To date, small-molecule ligands have been discovered for only a limited number of E3 ligases, which is an important limiting factor for realizing the full potential of targeted protein degradation. We report herein the discovery by chemical proteomics of azetidine acrylamides that stereoselectively and site-specifically react with a cysteine (C1113) in the E3 ligase substrate receptor DCAF1. We demonstrate that the azetidine acrylamide ligands for DCAF1 can be developed into electrophilic proteolysis-targeting chimeras (PROTACs) that mediated targeted protein degradation in human cells. We show that this process is stereoselective and does not occur in cells expressing a C1113A mutant of DCAF1. Mechanistic studies indicate that only low fractional engagement of DCAF1 is required to support protein degradation by electrophilic PROTACs. These findings, taken together, demonstrate how the chemical proteomic analysis of stereochemically defined electrophilic compound sets can uncover ligandable sites on E3 ligases that support targeted protein degradation.
靶向蛋白降解诱导的杂双功能化合物和分子胶呈现出令人兴奋的化学探针和药物发现途径。迄今为止，仅发现了少数 E3 连接酶的小分子配体，这是实现靶向蛋白降解全部潜力的一个重要限制因素。我们在此报告了通过化学蛋白质组学发现的吖丁啶丙烯酰胺，它可以立体选择性和特异性地与 E3 连接酶底物受体 DCAF1 中的半胱氨酸（C1113）反应。我们证明，DCAF1 的吖丁啶丙烯酰胺配体可以开发成亲电蛋白水解靶向嵌合体（PROTACs），在人细胞中介导靶向蛋白降解。我们表明，该过程是立体选择性的，并且不会在表达 DCAF1 的 C1113A 突变体的细胞中发生。机制研究表明，仅需要低分数的 DCAF1 参与即可支持亲电 PROTACs 的蛋白降解。这些发现表明，化学蛋白质组学分析立体化学定义的亲电化合物集如何可以揭示支持靶向蛋白降解的 E3 连接酶上可配体的位点。
