Cryo-EM structure of a bacteriophage T4 gp24 bypass mutant: the evolution of pentameric vertex proteins in icosahedral viruses.
ABSTRACT Many large viral capsids require special pentameric proteins at their fivefold vertices. Nevertheless, deletion of the special vertex protein gene product 24 (gp24) in bacteriophage T4 can be compensated by mutations in the homologous major capsid protein gp23. The structure of such a mutant virus, determined by cryo-electron microscopy to 26 angstroms, shows that the gp24 pentamers are replaced by mutant major capsid protein (gp23) pentamers at the vertices, thus re-creating a viral capsid prior to the evolution of specialized major capsid proteins and vertex proteins. The mutant gp23* pentamer is structurally similar to the wild-type gp24* pentamer but the insertion domain is slightly more distant from the gp23* pentamer center. There are additional SOC molecules around the gp23* pentamers in the mutant virus that were not present around the gp24* pentamers in the wild-type virus.
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ABSTRACT: The tailed double-stranded DNA bacteriophages, or Caudovirales, constitute ~96% of all the known phages. Although these phages come in a great variety of sizes and morphology, their virions are mainly constructed of similar molecular building blocks via similar assembly pathways. Here we review the structure of tailed double-stranded DNA bacteriophages at a molecular level, emphasizing the structural similarity and common evolutionary origin of proteins that constitute these virions.Bacteriophage 01/2014; 4(1):e28281.
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ABSTRACT: The head of bacteriophage T4 is decorated with 155 copies of the highly antigenic outer capsid protein (Hoc). One Hoc molecule binds near the center of each hexameric capsomer. Hoc is dispensable for capsid assembly and has been used to display pathogenic antigens on the surface of T4. Here we report the crystal structure of a protein containing the first three of four domains of Hoc from bacteriophage RB49, a close relative of T4. The structure shows an approximately linear arrangement of the protein domains. Each of these domains has an immunoglobulin-like fold, frequently found in cell attachment molecules. In addition, we report biochemical data suggesting that Hoc can bind to Escherichia coli, supporting the hypothesis that Hoc could attach the phage capsids to bacterial surfaces and perhaps also to other organisms. The capacity for such reversible adhesion probably provides survival advantages to the bacteriophage.Journal of Virology 06/2011; 85(16):8141-8. · 5.08 Impact Factor
Article: Bacteriophage assembly.[show abstract] [hide abstract]
ABSTRACT: Bacteriophages have been a model system to study assembly processes for over half a century. Formation of infectious phage particles involves specific protein-protein and protein-nucleic acid interactions, as well as large conformational changes of assembly precursors. The sequence and molecular mechanisms of phage assembly have been elucidated by a variety of methods. Differences and similarities of assembly processes in several different groups of bacteriophages are discussed in this review. The general principles of phage assembly are applicable to many macromolecular complexes.Viruses 03/2011; 3(3):172-203. · 2.51 Impact Factor