title: The entry mechanism of membrane-containing phage Bam35 infecting Bacillus thuringiensis.
abstract: The temperate double-stranded DNA bacteriophage Bam35 infects gram-positive Bacillus thuringiensis cells. Bam35 has an icosahedral protein coat surrounding the viral membrane that encloses the linear 15-kbp DNA genome. The protein coat of Bam35 uses the same assembly principle as that of PRD1, a lytic bacteriophage infecting gram-negative hosts. In this study, we dissected the process of Bam35 entry into discrete steps: receptor binding, peptidoglycan penetration, and interaction with the plasma membrane (PM). Bam35 very rapidly adsorbs to the cell surface, and N-acetyl-muramic acid is essential for Bam35 binding. Zymogram analysis demonstrated that peptidoglycan-hydrolyzing activity is associated with the Bam35 virion. We showed that the penetration of Bam35 through the PM is a divalent-cation-dependent process, whereas adsorption and peptidoglycan digestion are not.
authors.affiliation: Department of Biological and Environmental Sciences and Institute of Biotechnology, Biocenter 2, P.O. Box 56 (Viikinkaari 5), 00014 University of Helsinki, Finland.
authors.forename: Ausra
authors.initials: A
authors.lastname: Gaidelyte
authors.forename: Virginija
authors.initials: V
authors.lastname: Cvirkaite-Krupovic
authors.forename: Rimantas
authors.initials: R
authors.lastname: Daugelavicius
authors.forename: Jaana K H
authors.initials: JK
authors.lastname: Bamford
authors.forename: Dennis H
authors.initials: DH
authors.lastname: Bamford
mesh_terms: D017103:Bacillus Phages / Q000378:metabolism*; D001413:Bacillus thuringiensis / Q000821:virology*; D002462:Cell Membrane / Q000821:virology; D010450:Endopeptidases / Q000378:metabolism; D009112:Muramic Acids / Q000737:chemistry; D011991:Receptors, Virus / Q000737:chemistry / Q000502:physiology
chemical_list: D009112:Muramic Acids; D011991:Receptors, Virus; C031651:N-acetylmuramic acid; D010450:Endopeptidases; C001143:endolysin