Picornaviral processing: Some new ideas

✍ Scribed by Ann C. Palmenberg

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 527 KB
• Volume: 33
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240330306

✦ Synopsis

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.