(SARS-CoV-2) Papain-like Protease
SARS-CoV is an enveloped, single and positive-stranded RNA virus. Replication of the genomic RNA of SARS-CoV is mediated by replicase polyproteins that are processed by two viral proteases, papain-like protease (PLpro) and 3C-like protease (3CLpro). The chymotrypsin-like 3CLpro processes the replicase polyprotein at 11 sites, including cleaving itself from the polyprotein to generate a 25-kDa protease product. Papain-like proteases have been shown to process the amino-terminal end of the replicase polyprotein to generate two or three replicase products. Proteolytic processing of the coronavirus replicase polyprotein is essential for generating a functional replication complex. Therefore, the coronavirus replicase-encoded proteases, 3CLpro and PLpro, are potential targets for antiviral drug development.