Insights into the mechanism of SARS-CoV-2 main protease autocatalytic maturation from model precursors
- National Institutes of Health (NIH), Bethesda, MD (United States)
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- New England Biolabs, Ipswich, MA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
A critical step for SARS-CoV-2 assembly and maturation involves the autoactivation of the main protease (MProWT) from precursor polyproteins. Upon expression, a model precursor of MProWT mediates its own release at its termini rapidly to yield a mature dimer. A construct with an E290A mutation within MPro exhibits time dependent autoprocessing of the accumulated precursor at the N-terminal nsp4/nsp5 site followed by the C-terminal nsp5/nsp6 cleavage. In contrast, a precursor containing E290A and R298A mutations (MProM) displays cleavage only at the nsp4/nsp5 site to yield an intermediate monomeric product, which is cleaved at the nsp5/nsp6 site only by MProWT. MProM and the catalytic domain (MPro1-199) fused to the truncated nsp4 region also show time-dependent conversion in vitro to produce MProM and MPro1-199, respectively. The reactions follow first-order kinetics indicating that the nsp4/nsp5 cleavage occurs via an intramolecular mechanism. These results support a mechanism involving an N-terminal intramolecular cleavage leading to an increase in the dimer population and followed by an intermolecular cleavage at the C-terminus. Thus, targeting the predominantly monomeric MPro precursor for inhibition may lead to the identification of potent drugs for treatment.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Structural Molecular Biology (CSMB)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER); National Institutes of Health (NIH)
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 2217736
- Journal Information:
- Communications Biology, Journal Name: Communications Biology Journal Issue: 1 Vol. 6; ISSN 2399-3642
- Publisher:
- Springer NatureCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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