Key Points
- To identify the viral protein and biochemical mechanism responsible for the post-translational maturation of the encephalomyocarditis virus capsid precursor.
- Translated encephalomyocarditis virus RNA in cell-free translation systems derived from uninfected and virus-infected Krebs ascites cells.
- Analyzed translation products and peptide fragments using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and cyanogen bromide cleavage mapping.
- Purified the viral proteolytic activity from infected cell extracts using DEAE-cellulose and cellulose phosphate column chromatography.
- Translation in uninfected cell extracts generated a 112,000-Da polypeptide, whereas infected cell extracts produced a 100,000-Da product identical to in vivo capsid precursor A alongside a 12,500-Da N-terminal cleavage fragment.
- The endopeptidase activity responsible for processing the precursor copurified through two chromatographic steps with the 23,000-Da viral capsid protein gamma.
Structured PICO
PPopulationCell-free system from uninfected and virus-infected Krebs ascites cells
IInterventionTranslation of encephalomyocarditis virus RNA
CComparatorUninfected vs virus-infected cell-free systems
OOutcomeSynthesis of polypeptide products and identification of proteolytic activitysurrogate
The study suggests that the viral capsid protein gamma acts as a proteolytic enzyme involved in the maturation of the encephalomyocarditis virus capsid precursor.