Identification of a viral protein involved in post-translational maturation of the encephalomyocarditis virus capsid precursor.
Translation of encephalomyocarditis virus RNA in a cell-free system from uninfected Krebs ascites cells results in the synthesis of a major polypeptide product with a molecular weight of approximately 112,000. In contrast, when the viral RNA is translated in a cell-free system from virus-infected cells, this polypeptide is absent and the largest polypeptide produced has a molecular weight of about 100,000. This latter polypeptide comigrates on sodium dodecyl sulfate-gels with in vivo virus capsid precursor A, and the two have identical patterns of CNBr-generated peptides. A polypeptide having a molecular weight of 12,500 is also a major translation product in the system from infected cells (but not from uninfected cells). This polypeptide appears to be generated by cleavage of the NH-2-terminal portion of the viral RNA-dependent polypeptides by a proteolytic activity present in the infected cell-free system. This proteolytic activity copurifies with the 23,000-molecular weight viral capsid protein gamma, found in infected cells, through chromatography on DEAE-cellulose and cellulose phosphate. This suggests that gamma is itself a proteolytic enzyme involved in maturation of the viral capsid precursor.
D000818:Animals; D001345:Autoradiography; D002287:Carcinoma, Krebs 2; D002460:Cell Line; D002474:Cell-Free System; D002848:Chromatography, DEAE-Cellulose; D003488:Cyanogen Bromide; D004591:Electrophoresis, Polyacrylamide Gel; D004686:Encephalomyocarditis virus; D008970:Molecular Weight; D010452:Peptide Biosynthesis; D014176:Protein Biosynthesis; D011498:Protein Precursors; D012367:RNA, Viral; D014764:Viral Proteins
D011498:Protein Precursors; D012367:RNA, Viral; D014764:Viral Proteins; D003488:Cyanogen Bromide