Structure-Based Design of a Cyclic Peptide Inhibitor of the SARS-CoV-2 Main Protease

This paper presents the design and study of a first-in-class cyclic peptide inhibitor against the SARS-CoV-2 main protease (Mpro). The cyclic peptide inhibitor is designed to mimic the conformation of a substrate at a C-terminal autolytic cleavage site of Mpro. Synthesis and evaluation of a first-generation cyclic peptide inhibitor reveals that the inhibitor is active against Mpro in vitro and is non-toxic toward human cells in culture. The initial hit described in this manuscript, UCI-1, lays the groundwork for the development of additional cyclic peptide inhibitors against Mpro with improved activities.