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A minor capsid protein P30 is essential for bacteriophage PRD1 capsid assembly

P S Rydman1, J K Bamford, D H Bamford

  • 1Department of Biosciences and Institute of Biotechnology Viikki Biocenter, University of Helsinki, 00014, Finland.

Journal of Molecular Biology
|November 8, 2001
PubMed

Insights

Bacteriophage PRD1 assembly requires protein P30 for stable capsid formation. Without P30, an empty membrane vesicle forms, highlighting P30's crucial role in viral structure.

Area of Science:

  • Virology
  • Structural Biology
  • Molecular Biology

Background:

  • Bacteriophage PRD1 is a double-stranded DNA virus with an internal membrane within its isometric capsid.
  • The capsid is composed of major capsid protein P3 and a minor protein, P30 (9 kDa).

Purpose of the Study:

  • To investigate the role of protein P30 in the assembly and structural integrity of bacteriophage PRD1 capsids.
  • To understand the formation of phage-specific membrane vesicles in the absence of protein P30.

Main Methods:

  • Structural analysis of bacteriophage PRD1.
  • Analysis of capsid assembly intermediates and final structures.
  • Identification of protein components in assembled capsids and membrane vesicles.

Main Results:

  • Protein P30 is proposed to localize between adjacent facets of the icosahedral capsid.
  • Protein P30 is essential for the stable assembly of the bacteriophage PRD1 capsid.
  • In the absence of P30, an empty phage-specific membrane vesicle is formed.
  • Protein P10, a phage-encoded assembly factor, is the major component of these P30-deficient vesicles and is not found in the mature virion.

Conclusions:

  • Protein P30 plays a critical role in ensuring the stable assembly of the bacteriophage PRD1 capsid.
  • The formation of empty membrane vesicles lacking P30 suggests an alternative assembly pathway or a failure in proper capsid maturation.
  • Protein P10 acts as an assembly factor during capsid formation but is excluded from the final virion structure.

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