Biochemical and structural insights into SARS-CoV-2 polyprotein processing by Mpro (HDX-MS pulse labeling)

ABSTRACT: SARS-CoV-2, a human coronavirus, is the causative agent of the COVID-19 pandemic, entailing enormous disruption worldwide. Its ~30 kb RNA genome is translated into two large polyproteins subsequently cleaved by viral papain-like protease and main protease (Mpro/nsp5). Polyprotein processing is essential yet incompletely understood. We studied Mpro-mediated processing of the nsp7-10/11 polyprotein, whose mature products are cofactors of the viral replicase, identifying the order of cleavages: 1) nsp9-10, 2) nsp8-9/nsp10-11, and 3) nsp7-8. Integrative modeling based on mass spectrometry (including hydrogen-deuterium exchange and cross-linking) and X-ray scattering yielded three-dimensional models of the nsp7-10/11 polyprotein, and the data suggest that the nsp7-10/11 structure in complex with Mpro strongly resembles the unbound polyprotein. Our array of techniques supports the notion that interplay between polyprotein conformation and junction accessibility determine the preference and order of cleavages. Finally, we leveraged assays of limited proteolysis by Mpro of nsp7-11 using a series of inhibitors/binders to characterize Mpro inhibition using a polyprotein substrate.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Severe Acute Respiratory Syndrome Coronavirus 2

SUBMITTER: Valentine Courouble  

LAB HEAD: Patrick R Griffin

PROVIDER: PXD033702 | Pride | 2022-12-19

REPOSITORIES: Pride