Hydrolases;
Acting on peptide bonds (peptidases);
Serine endopeptidases
Reaction(IUBMB)
Leu is conserved at position P1 for all four cleavage sites. Alanine is found at position P1' of the NS4A-NS4B cleavage site, whereas serine is found at position P1' of the NS3-NS4A, NS4B-NS5A and NS5A-NS5B cleavage sites
Comment
The polyprotein of noncytopathogenic pestiviruses is cleaved co- and post-translationally into at least 11 proteins (Npro, C, Erns, E1, E2, p7, NS2-3, NS4A, NS4B, NS5A, and NS5B) [2]. The genomes of cytopathogenic pestivirus strains express at least one additional protein, called NS3 (p80) [2]. This enzyme, which resides in the N-terminal region of NS3 (nonstructural protein 3), is essential for generation of its own C-terminus and for processing of the downstream cleavage sites, leading to the release of the pestivirus nonstructural proteins NS4A, NS4B, NS5A and NS5B [1,2]. Belongs in peptidase family S31.
Xu J, Mendez E, Caron PR, Lin C, Murcko MA, Collett MS, Rice CM.
Title
Bovine viral diarrhea virus NS3 serine proteinase: polyprotein cleavage sites, cofactor requirements, and molecular model of an enzyme essential for pestivirus replication.
NS3 serine protease of bovine viral diarrhea virus: characterization of active site residues, NS4A cofactor domain, and protease-cofactor interactions.
