Methods: Coronavirus main protease (Mpro) is an integral component of the viral genome, which is essential for viral replication through proteolytic processing of RNA replicase machinery. We crystalized HCoV-NL63 Mprocomplexed with a Michael acceptor inhibitor N3, and determined the enzymatic kinetics of the mechanism-based irreversible enzyme inhibition.
Results: Structural analysis, consistent with biochemical inhibition results, revealed the molecular mechanism of enzyme inhibition at the highly conservative substrate-recognition pocket. We showed such molecular target remains unchanged across 30 clinical isolates of HCoV-NL63 strains. Through comparative study with Mpros from other HCoVs (including the deadly SARS-CoV and MERS-CoV) and their related zoonotic coronaviruses, we show that the structure of HCoV-NL63 Mproserves as an important prototype for rational development of antiviral therapeutics to treat human diseases caused by existing or possibly newly emerging coronaviruses.
Conclusion: The crystal structure of HCoV-NL63 Mpro complexed with inhibitor N3 has provided critical insight into the design of irreversible inhibitor carrying a Michael acceptor warhead. Through detailed sequence and structural comparison, we validated the feasibility of this compound as broad spectrum therapeutic for both existing and possibly emerging human coronaviruses. Further pharmaceutical development of such covalent peptidomimetic inhibitors would yield success in clinical management of human coronavirus diseases and public health preparedness for potential future pandemic.
C. Chen, None
H. Yang, None