title: The Holin protein of bacteriophage PRD1 forms a pore for small-molecule and endolysin translocation.
abstract: PRD1 is a bacteriophage with an icosahedral outer protein layer surrounding the viral membrane, which encloses the linear double-stranded DNA genome. PRD1 infects gram-negative cells harboring a conjugative IncP plasmid. Here we studied the lytic functions of PRD1. Using infected cells and plasmid-borne lysis genes, we demonstrated that a two-component lysis system (holin-endolysin) operates to release progeny phage particles from the host cell. Monitoring of ion fluxes and the ATP content of the infected cells allowed us to build a model of the sequence of lysis-related physiological changes. A decrease in the intracellular level of ATP is the earliest indicator of cell lysis, followed by the leakage of K+ from the cytosol approximately 20 min prior to the decrease in culture turbidity. However, the K+ efflux does not immediately lead to the depolarization of the cytoplasmic membrane or leakage of the intracellular ATP. These effects are observed only approximately 5 to 10 min prior to cell lysis. Similar results were obtained using cells expressing the holin and endolysin genes from plasmids.
authors: Biocenter 2, P.O. Box 56 (Viikinkaari 5), FIN-00014 University of Helsinki, Finland.
authors: Gabija
authors: G
authors: Ziedaite
authors: Rimantas
authors: R
authors: Daugelavicius
authors: Jaana K H
authors: JK
authors: Bamford
authors: Dennis H
authors: DH
authors: Bamford
mesh_terms: D001433:Bacteriolysis; D025622:Bacteriophage PRD1 / Q000235:genetics / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D002463:Cell Membrane Permeability; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism*; D005814:Genes, Viral; D005816:Genetic Complementation Test; D007477:Ions / Q000378:metabolism; D009861:Onium Compounds; D009943:Organophosphorus Compounds; D011188:Potassium / Q000378:metabolism; D019779:Salmonella enterica / Q000235:genetics / Q000502:physiology / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D007477:Ions; D009861:Onium Compounds; D009943:Organophosphorus Compounds; C492233:P35 protein, Enterobacteria phage PRD1; D014764:Viral Proteins; D010450:Endopeptidases; C001143:endolysin; D011188:Potassium; C013289:tetraphenylphosphonium