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Phage Phenomics: Physiological Approaches to Characterize Novel Viral Proteins
Published on: June 11, 2015
Structural organization of Bacillus subtilis phage phi29. A model.
J L Carrascosa1, E Méndez, J Corral
1Centro de Biología Molecular (CSIC-UAM), Universidad Autónoma de Madrid, Canto Blanco, Madrid-34, Spain.
Virology
|June 1, 1981
Summary
Researchers studied the structure of phage phi29, a non-isometric virus. They found its capsid is a prolate icosahedron composed of protein p8 dimers clustered in trimers, with protein p8.5 forming the fibers.
Area of Science:
- Virology
- Structural Biology
- Molecular Biology
Background:
- Phage phi29 is a non-isometric virus known to produce morphological variants during infection.
- Understanding the precise structure of viral capsids is crucial for comprehending viral assembly and function.
Purpose of the Study:
- To elucidate the structural composition of the phage phi29 capsid.
- To determine the arrangement and stoichiometry of structural proteins within the phage phi29 particle.
Main Methods:
- Electron microscopy was used to analyze morphological variants of phage phi29.
- Comparative analysis with T-even phages informed capsid geometry.
- Calculation of protein subunit numbers based on phage molecular weight, individual protein molecular weights, and mass percentages.
- Chemical crosslinking was employed to investigate protein-protein interactions within the capsid.
Main Results:
- The capsid of phage phi29 was determined to be a prolate icosahedron.
- The major capsid protein is p8, and protein p8.5 constitutes the fibers.
- Stoichiometric analysis indicated specific numbers of protein subunits per viral particle.
- Chemical crosslinking data suggested that protein p8 exists as dimers clustered into trimers within the capsid structure.
Conclusions:
- The phage phi29 capsid exhibits a prolate icosahedral structure.
- The capsid is primarily composed of protein p8, organized as trimeric clusters of dimers, with p8.5 forming fibers.
- These findings provide detailed insights into the molecular architecture of phage phi29.
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