title: Peptidoglycan hydrolytic activities associated with bacteriophage virions.
abstract: Murein hydrolases appear to be widespread in the virions of bacteriophages infecting Gram-positive or Gram-negative bacteria. Muralytic activity has been found in virions of the majority of a diverse collection of phages. Where known, the enzyme is either part of a large protein or found associated with other structural components of the virion that limit enzyme activity. In most cases, the lack of genetic and structural characterization of the phage precludes making a definitive identification of the enzymatic protein species. However, three proteins with muralytic activity have been unequivocally identified. T7gp16 is a 144 kDa internal head protein that is ejected into the cell at the initiation of infection; its enzyme activity is required only when the cell wall is more highly cross-linked. P22gp4 is part of the neck of the particle and is essential for infectivity. The activity associated with virions of Bacillus subtilis phage ø29 and its relatives lies in the terminal protein gp3. These studies lead to a general mechanism describing how phage genomes are transported across the bacterial cell wall.
authors.affiliation: Molecular Genetics and Microbiology, and Institute for Cell and Molecular Biology, University of Texas, Austin, TX 78712-1095, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Moak
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Molineux
mesh_terms: D017103:Bacillus Phages / Q000201:enzymology; D017100:Bacteriophage P22 / Q000201:enzymology; D017123:Bacteriophage T7 / Q000201:enzymology; D001435:Bacteriophages / Q000201:enzymology*; D002473:Cell Wall / Q000378:metabolism; D005814:Genes, Viral; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism; D010457:Peptidoglycan / Q000378:metabolism*; D014758:Viral Core Proteins / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism; D015678:Viral Structural Proteins / Q000378:metabolism; D014771:Virion / Q000201:enzymology*
chemical_list: D010457:Peptidoglycan; D014758:Viral Core Proteins; D014764:Viral Proteins; D015678:Viral Structural Proteins; C412714:gene16 product, bacteriophage T7; C061994:p3 protein, bacteriophage phi 29; D006026:Glycoside Hydrolases