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Multimerization of the p12 domain is necessary for Mason-Pfizer monkey virus Gag assembly in vitro

Zdenek Knejzlík1, Zdena Smékalová, Tomás Ruml

  • 1Department of Biochemistry and Microbiology and Center for Integrated Genomics, Institute of Chemical Technology, Prague 166 28, Czech Republic.

Virology
|May 11, 2007
PubMed

Insights

The Mason-Pfizer monkey virus Gag protein

Area of Science:

  • Virology
  • Molecular Biology
  • Structural Biology

Background:

  • The Mason-Pfizer monkey virus (M-PMV) Gag protein possesses a unique p12 domain.
  • The p12 domain's N-terminal half exhibits alpha-helical structure with a leucine zipper-like region.
  • The C-terminal half of p12 can form SDS-resistant oligomers in vitro, suggesting protein-protein interaction capabilities.

Purpose of the Study:

  • To investigate the oligomerization potential of the M-PMV p12 domain.
  • To analyze the role of leucine zippers within p12 in Gag-Gag oligomerization.
  • To understand the scaffold-like function of the p12 domain in viral assembly.

Main Methods:

  • Expression and purification of recombinant p12 and its mutants in E. coli.
  • Analysis of p12 oligomerization using chemical cross-linking experiments.
  • Expression of Gag precursor with p12 mutants in vitro and in cells.
  • Assessment of viral assembly using a cell-free system.

Main Results:

  • Purified p12 mutants formed various oligomers, confirmed by cross-linking.
  • p12 mutants within the Gag precursor assembled when overexpressed in cells.
  • All p12 mutants, including leucine zipper variants, were assembly-defective in a cell-free system.
  • A region with alternating leucines and isoleucines in p12 is crucial for its function.

Conclusions:

  • The p12 domain is a critical protein-protein interaction module facilitating Gag oligomerization.
  • The leucine zipper-like region and alternating leucines/isoleucines in p12 are important for Gag assembly.
  • The scaffold function of p12 in viral assembly is complex and context-dependent, extending beyond simple oligomerization.

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