Polyprotein processing in echovirus 22: a first assessment.
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.
Schultheiss
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National Institutes of Health, Hepatitis Viruses Section, Bethesda, MD 20892-0740, USA.
Emerson
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Purcell
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Gauss-Müller
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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
D011506:Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases