Expedited Approach toward the Rational Design of Noncovalent SARS-CoV-2 Main Protease Inhibitors

The main protease MPpro of SARS-CoV-2 is a validated antiviral drug target. Several MPpro inhibitors have been reported with potent enzymatic inhibition and cellular antiviral activity, including GC376, boceprevir, calpain inhibitors II, and XII, with each containing a reactive warhead that covalently modifies the catalytic Cys145. Coupling structure-based drug design with the one-pot Ugi four-component reaction, we discovered one of the most potent noncovalent inhibitors, 23R (Jun8-76-3A) that is structurally distinct from the canonical MPpro inhibitor GC376. Significantly, 23R is highly selective compared with covalent inhibitors such as GC376, especially toward host proteases. The cocrystal structure of SARS-CoV-2 MPpro with 23R revealed a previously unexplored binding site located in between the S2 and S4 pockets. Overall, this study discovered 23R, one of the most potent and selective noncovalent SARS-CoV-2 MPpro inhibitors reported to date, and a novel binding pocket in MPpro that can be explored for inhibitor design.

Automated summary

This study discovered 23R, one of the most potent and selective noncovalent SARS-CoV-2 MPpro inhibitors reported to date, and a novel binding pocket in MPpro that can be explored for inhibitor design.