title: Polyprotein processing in echovirus 22: a first assessment.
abstract: The major steps of the polyprotein processing of Echovirus 22 (EV22), a highly unusual member of the picornavirus family, have been characterized for the first time by employing in vitro assay systems. Cell-free expression of a P1-2ABC precursor as well as VP1-2A yielded autoproteolytically inactive proteins, suggesting that the 2A region of the EV22 polyprotein does not contain a proteolytic activity. The intra- and intermolecular cleavage specificity of proteinase 3C, the major proteolytic enzyme in picornaviruses, was studied by expressing the enzyme of EV22 in a bacterial system as well as in the framework of precursor molecules generated by in vitro transcription/translation in a cell-free system. A VP1-2A percursor could very efficiently be cleaved in trans by the recombinant 3C, whereas the junction between P2 and P3 remained uncleaved. Expression of the complete P3-region in the cell-free system led to the autocatalytic release of large amounts of p22, a protein of the predicted molecular weight of the EV22 proteinase 3C that was recognized by an antibody raised against the recombinant enzyme.
authors.affiliation: National Institutes of Health, Hepatitis Viruses Section, Bethesda, MD 20892-0740, USA.
authors.forename: T
authors.initials: T
authors.lastname: Schultheiss
authors.forename: S U
authors.initials: SU
authors.lastname: Emerson
authors.forename: R H
authors.initials: RH
authors.lastname: Purcell
authors.forename: V
authors.initials: V
authors.lastname: Gauss-Müller
mesh_terms: D000086042:3C Viral Proteases; D003546:Cysteine Endopeptidases / Q000378:metabolism; D029822:Enterovirus B, Human / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral; D008970:Molecular Weight; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D014764:Viral Proteins
chemical_list: D011506:Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases