Analysis of the molecular determinants for furin cleavage of the spike protein S1/S2 site in defined strains of the prototype coronavirus murine hepatitis virus (MHV).

Autor: Choi A; Departments of Microbiology & Immunology, Cornell University, Ithaca, NY, USA., Kots ED; Department of Physiology & Biophysics, New York, NY, USA; Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, USA., Singleton DT; Departments of Microbiology & Immunology, Cornell University, Ithaca, NY, USA., Weinstein H; Department of Physiology & Biophysics, New York, NY, USA; Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, USA. Electronic address: haw2002@med.cornell.edu., Whittaker GR; Departments of Microbiology & Immunology, Cornell University, Ithaca, NY, USA; Public & Ecosystem Health, Cornell University, Ithaca, NY, USA. Electronic address: grw7@cornell.edu.
Jazyk: angličtina
Zdroj: Virus research [Virus Res] 2024 Feb; Vol. 340, pp. 199283. Date of Electronic Publication: 2023 Dec 09.
DOI: 10.1016/j.virusres.2023.199283
Abstrakt: We analyzed the spike protein S1/S2 cleavage of selected strains of a prototype coronavirus, mouse hepatitis virus (MHV) by the cellular protease furin, in order to understand the structural requirements underlying the sequence selectivity of the scissile segment. The probability of cleavage of selected MHV strains was first evaluated from furin cleavage scores predicted by the ProP computer software, and then cleavage was measured experimentally with a fluorogenic peptide cleavage assay consisting of S1/S2 peptide mimics and purified furin. We found that in vitro cleavability varied across MHV strains in line with predicted results-but with the notable exception of MHV-A59, which was not cleaved despite a high score predicted for its sequence. Using the known X-Ray structure of furin in complex with a substrate-like inhibitor as an initial structural reference, we carried out molecular dynamics (MD) simulations to learn the modes of binding of the peptides in the furin active site, and the suitability of the complex for initiation of the enzymatic cleavage. We identified the 3D structural requirements of the furin active site configuration that enable bound peptides to undergo cleavage, and the way in which the various strains tested experimentally are fulfilling these requirements. We find that despite some flexibility in the organization of the peptide bound to the active site of the enzyme, the presence of a histidine at P2 of MHV-A59 fails to properly orient the sidechain of His194 of the furin catalytic triad and therefore produces a distortion that renders the peptide/complex structural configuration in the active site incompatible with requirements for cleavage initiation. The Ser/Thr in P1 of MHV-2 and MHV-S has a similar effect of distorting the conformation of the furin active site residues produced by the elimination of the canonical salt-bridge formed by arginine in P1 position. This work informs a study of coronavirus infection and pathogenesis with respect to the function of the viral spike protein, and suggests an important process of viral adaptation and evolution within the spike S1/S2 structural loop.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: