Structural basis for the inhibition of coronaviral main proteases by PF-00835231.

The main protease (M ^pro) of coronaviruses plays a key role in viral replication, thus serving as a hot target for drug design. PF-00835231 is a promising inhibitor of SARS-CoV-2 M ^pro. Here, we report the inhibitory potency of PF-00835231 against SARS-CoV-2 M ^pro and seven M ^pro mutants (G15S, M49I, Y54C, K90R, P132H, S46F, and V186F) from SARS-CoV-2 variants. The results confirm that PF-00835231 has broad-spectrum inhibition against various coronaviral M ^pros. In addition, the crystal structures of SARS-CoV-2 M ^pro, SARS-CoV M ^pro, MERS-CoV M ^pro, and seven SARS-CoV-2 M ^pro mutants (G15S, M49I, Y54C, K90R, P132H, S46F, and V186F) in complex with PF-00835231 are solved. A detailed analysis of these structures reveals key determinants essential for inhibition and elucidates the binding modes of different coronaviral M ^pros. Given the importance of the main protease for the treatment of coronaviral infection, structural insights into M ^pro inhibition by PF-00835231 can accelerate the design of novel antivirals with broad-spectrum efficacy against different human coronaviruses.