Exchange of the coronavirus replicase polyprotein cleavage sites alters protease specificity and processing.
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.
Gadlage
Mark J
MJ
Department of Pediatrics, Vanderbilt University Medical Center, 1161 21st Ave. S., Nashville, TN 37232-2581, USA.
Denison
Mark R
MR
D006517:Murine hepatitis virus / Q000235:genetics / Q000502:physiology*; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D020815:Polyproteins / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
D020815:Polyproteins; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase; D010447:Peptide Hydrolases