title: Purified membrane-containing procapsids of bacteriophage PRD1 package the viral genome.
abstract: Icosahedral-tailed double-stranded DNA (dsDNA) bacteriophages and herpesviruses translocate viral DNA into a preformed procapsid in an ATP-driven reaction by a packaging complex that operates at a portal vertex. A similar packaging system operates in the tailless dsDNA phage PRD1 (Tectiviridae family), except that there is an internal membrane vesicle in the procapsid. The unit-length linear dsDNA genome with covalently linked 5'-terminal proteins enters the procapsid through a unique vertex. Two small integral membrane proteins, P20 and P22, provide a conduit for DNA translocation. The packaging machinery also contains the packaging ATPase P9 and the packaging efficiency factor P6. Here we describe a method used to obtain purified packaging-competent PRD1 procapsids. The optimized in vitro packaging system allowed efficient packaging of defined DNA substrates. We determined that the genome terminal protein P8 is necessary for packaging and provided an estimation of the packaging rate.
authors.affiliation: Department of Biological and Environmental Sciences and Institute of Biotechnology, University of Helsinki, PO Box 56, FIN-00014 Helsinki, Finland.
authors.forename: Gabija
authors.initials: G
authors.lastname: Ziedaite
authors.forename: Hanna M
authors.initials: HM
authors.lastname: Kivelä
authors.forename: Jaana K H
authors.initials: JK
authors.lastname: Bamford
authors.forename: Dennis H
authors.initials: DH
authors.lastname: Bamford
mesh_terms: D025622:Bacteriophage PRD1 / Q000502:physiology*; D002213:Capsid / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D004279:DNA, Viral / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D050296:Microbial Viability; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000378:metabolism; D019065:Virus Assembly
chemical_list: D004279:DNA, Viral; D008565:Membrane Proteins; D014764:Viral Proteins