Related Experiment Videos
Mengo virus maturation is accompanied by C-terminal modification of capsid protein VP1
1Department of Biochemistry, University of Alberta, Edmonton, Canada.
Abstract:
We have demonstrated that the C-terminal ends of the VP1 proteins of Mengo virus undergo a postassembly trimming of three amino acid residues. A variable proportion of the VP1 molecules isolated from purified virions terminate at Glu 277, which corresponds to the initial viral protease 3C cleavage site. The remainder of the VP1 molecules terminates at Leu 274. When chymotrypsin treatment is included in the virus purification procedure, Leu 274 is the exclusive C-terminal amino acid of the VP1 molecules. The trimming process was found to influence the pH-mediated dissociability of virions in vitro: this was demonstrated by sucrose gradient analysis and electron microscopy. Since long-term incubation of purified virions did not alter the C-terminal Glu 277/Leu 274 ratio, it appears that the trimming process is not autocatalytic.
Insights
Mengo virus VP1 proteins undergo postassembly trimming at their C-terminal ends, affecting viral particle stability. This trimming, influenced by purification methods, impacts pH-mediated virion dissociation.
Area of Science:
- Virology
- Structural Biology
- Molecular Biology
Background:
- The VP1 protein is a major structural component of Mengo virus.
- Post-translational modifications can significantly alter viral protein function and virion properties.
Purpose of the Study:
- To investigate the postassembly processing of Mengo virus VP1 protein C-termini.
- To determine the functional consequences of VP1 C-terminal modifications on virion stability.
Main Methods:
- Analysis of VP1 C-terminal amino acids in purified Mengo virions.
- Chymotrypsin treatment during virus purification.
- Sucrose gradient analysis and electron microscopy to assess virion dissociability.
Main Results:
- Mengo virus VP1 proteins exhibit C-terminal heterogeneity, terminating at Glu 277 or Leu 274.
- Chymotrypsin treatment during purification results in exclusive Leu 274 termination.
- VP1 C-terminal trimming influences pH-mediated dissociation of Mengo virions in vitro.
Conclusions:
- A postassembly trimming event modifies the C-terminus of Mengo virus VP1.
- This trimming affects virion stability and pH-dependent dissociation.
- The trimming process is likely not autocatalytic.