Molecular Mechanism of the Non-Covalent Orally Targeted SARS-CoV-2 M pro Inhibitor S-217622 and Computational Assessment of Its Effectiveness against Mainstream Variants.

Convenient and efficient therapeutic agents are urgently needed to block the continued spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, the mechanism for the novel orally targeted SARS-CoV-2 main protease (M ^pro ) inhibitor S-217622 is revealed through a molecular dynamics simulation. The difference in the movement modes of the S-217622-M ^pro complex and apo-M ^pro suggested S-217622 could inhibit the motility intensity of M ^pro , thus maintaining their stable binding. Subsequent energy calculations showed that the P2 pharmacophore possessed the highest energy contribution among the three pharmacophores of S-217622. Additionally, hot-spot residues H41, M165, C145, E166, and H163 have strong interactions with S-217622. To further investigate the resistance of S-217622 to six mainstream variants, the binding modes of S-217622 with these variants were elucidated. The subtle differences in energy compared to that of the wild type implied that the binding patterns of these systems were similar, and S-217622 still inhibited these variants. We hope this work will provide theoretical insights for optimizing novel targeted M ^pro drugs.