Exchange of the coronavirus replicase polyprotein cleavage sites alters protease specificity and processing

J Virol. 2010 Jul;84(13):6894-8. doi: 10.1128/JVI.00752-10. Epub 2010 Apr 28.

Abstract

Coronavirus nonstructural proteins 1 to 3 are processed by one or two papain-like proteases (PLP1 and PLP2) at specific cleavage sites (CS1 to -3). Murine hepatitis virus (MHV) PLP2 and orthologs recognize and cleave at a position following a p4-Leu-X-Gly-Gly-p1 tetrapeptide, but it is unknown whether these residues are sufficient to result in processing by PLP2 at sites normally cleaved by PLP1. We demonstrate that exchange of CS1 and/or CS2 with the CS3 p4-p1 amino acids in engineered MHV mutants switches specificity from PLP1 to PLP2 at CS2, but not at CS1, and results in altered protein processing and virus replication. Thus, the p4-p1 residues are necessary for PLP2 processing but require a specific protein or cleavage site context for optimal PLP recognition and cleavage.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Murine hepatitis virus / genetics
  • Murine hepatitis virus / physiology*
  • Peptide Hydrolases / genetics
  • Peptide Hydrolases / metabolism*
  • Polyproteins / genetics
  • Polyproteins / metabolism*
  • Protein Processing, Post-Translational
  • RNA-Dependent RNA Polymerase / genetics
  • RNA-Dependent RNA Polymerase / metabolism*
  • Substrate Specificity
  • Viral Proteins / genetics
  • Viral Proteins / metabolism*
  • Virus Replication*

Substances

  • Polyproteins
  • Viral Proteins
  • RNA-Dependent RNA Polymerase
  • Peptide Hydrolases