SARS-CoV-2 polyprotein substrate regulates the stepwise Mpro cleavage reaction

Author:

Narwal, Manju

Armache, Jean-Paul

Edwards,Thomas

Murakami, Katsuhiko S
Author Address

Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA., Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA; Center for Structural Biology, Huck Institute of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA. Electronic address: jza449@psu.edu., National Cryo-EM Facility, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research Inc., Frederick, MD 21702, USA., Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA; Center for Structural Biology, Huck Institute of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA; Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA. Electronic address: kum14@psu.edu.,

Abstract:

The processing of the Coronavirus polyproteins pp1a and pp1ab by the main protease Mpro to produce mature proteins is a crucial event in virus replication and a promising target for antiviral drug development. Mpro cleaves polyproteins in a defined order, but how Mpro and/or the polyproteins determine the order of cleavage remains enigmatic due to a lack of structural information about polyprotein-bound Mpro. Here, we present the cryo-EM structures of SARS-CoV-2 Mpro in an apo form and in complex with the nsp7-10 region of the pp1a polyprotein. The complex structure shows that Mpro interacts with only the recognition site residues between nsp9 and nsp10, without any association with the rest of the polyprotein. Comparison between the apo form and polyprotein-bound structures of Mpro highlights the flexible nature of the active site region of Mpro, which allows it to accommodate 10 recognition sites found in the polyprotein. These observations suggest that the role of Mpro in selecting a preferred cleavage site is limited and underscore the roles of the structure, conformation and/or dynamics of the polyproteins in determining the sequence of polyprotein cleavage by Mpro. Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.

See More

Author Address