title: Picornaviral processing: some new ideas.
abstract: Mature picornaviral proteins are derived by progressive, post-translational cleavage of a giant precursor polyprotein. At least three viral-encoded proteolytic activities are involved in the processing. The first cleavage takes place while the polyprotein is still nascent on a ribosome. In poliovirus, this event is probably catalyzed by peptide 2A, a protein from the middle portion of the genome. Most subsequent processing is effected by viral protease 3C, a thiol-type enzyme, responsible for eight to ten self-cleaving and autocatalytic reactions within the polyprotein. The final proteolytic processing event, maturation of the VPO peptide, may occur by a novel, autocatalytic, serine-type mechanism, where viral RNA serves as proton-acceptor during the cleavage reaction.
mesh_terms: D000595:Amino Acid Sequence; D010447:Peptide Hydrolases / Q000378:metabolism; D010849:Picornaviridae / Q000378:metabolism*; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D014764:Viral Proteins / Q000378:metabolism*; D015678:Viral Structural Proteins
chemical_list: D014764:Viral Proteins; D015678:Viral Structural Proteins; D010447:Peptide Hydrolases