Department of Biochemistry and Molecular Pharmacology; Schiffer Lab; Graduate School of Biomedical Sciences
Amino Acids, Peptides, and Proteins | Biochemistry, Biophysics, and Structural Biology | Ecology and Evolutionary Biology | Immunology and Infectious Disease | Infectious Disease | Medicinal Chemistry and Pharmaceutics | Medicinal-Pharmaceutical Chemistry | Microbiology | Virology
With the continual evolution of new strains of SARS-CoV-2 that are more virulent, transmissible, and able to evade current vaccines, there is an urgent need for effective anti-viral drugs SARS-CoV-2 main protease (M(pro)) is a leading target for drug design due to its conserved and indispensable role in the viral life cycle. Drugs targeting M(pro) appear promising but will elicit selection pressure for resistance. To understand resistance potential in M(pro), we performed a comprehensive mutational scan of the protease that analyzed the function of all possible single amino acid changes. We developed three separate high-throughput assays of M(pro) function in yeast, based on either the ability of M(pro) variants to cleave at a defined cut-site or on the toxicity of their expression to yeast. We used deep sequencing to quantify the functional effects of each variant in each screen. The protein fitness landscapes from all three screens were strongly correlated, indicating that they captured the biophysical properties critical to M(pro) function. The fitness landscapes revealed a non-active site location on the surface that is extremely sensitive to mutation making it a favorable location to target with inhibitors. In addition, we found a network of critical amino acids that physically bridge the two active sites of the M(pro) dimer. The clinical variants of M(pro) were predominantly functional in our screens, indicating that M(pro) is under strong selection pressure in the human population. Our results provide predictions of mutations that will be readily accessible to M(pro) evolution and that are likely to contribute to drug resistance. This complete mutational guide of M(pro) can be used in the design of inhibitors with reduced potential of evolving viral resistance.
S. cerevisiae, evolutionary biology, infectious disease, microbiology, SARS-CoV-2
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© 2022, Flynn et al. This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
DOI of Published Version
Flynn JM, Samant N, Schneider-Nachum G, Bakan DT, Yilmaz NK, Schiffer CA, Moquin SA, Dovala D, Bolon DNA. Comprehensive fitness landscape of SARS-CoV-2 Mpro reveals insights into viral resistance mechanisms. Elife. 2022 Jun 20;11:e77433. doi: 10.7554/eLife.77433. Epub ahead of print. PMID: 35723575. Link to article on publisher's site
Flynn J, Samant N, Nachum GS, Bakan DT, Yilmaz NK, Schiffer CA, Moquin SA, Dovala D, Bolon DN. (2022). Comprehensive fitness landscape of SARS-CoV-2 M(pro) reveals insights into viral resistance mechanisms. Schiffer Lab Publications. https://doi.org/10.7554/eLife.77433. Retrieved from https://escholarship.umassmed.edu/schiffer/49
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