title: Biochemical and structural characterisation of membrane-containing icosahedral dsDNA bacteriophages infecting thermophilic Thermus thermophilus.
abstract: Icosahedral dsDNA viruses isolated from hot springs and proposed to belong to the Tectiviridae family infect the gram-negative thermophilic Thermus thermophilus bacterium. Seven such viruses were obtained from the Promega Corporation collection. The structural protein patterns of three of these viruses, growing to a high titer, appeared very similar but not identical. The most stable virus, P23-77, was chosen for more detailed studies. Analysis of highly purified P23-77 by thin layer chromatography for neutral lipids showed lipid association with the virion. Cryo-EM based three-dimensional image reconstruction of P23-77 to 1.4 nm resolution revealed an icosahedrally-ordered protein coat, with spikes on the vertices, and an internal membrane. The capsid architecture of P23-77 is most similar to that of the archaeal virus SH1. These findings further complicate the grouping of icosahedrally-symmetric viruses containing an inner membrane. We propose a single superfamily or order with members in several viral families.
authors.affiliation: Department of Biological and Environmental Sciences and Institute of Biotechnology, Biocenter 2, FIN-00014, University of Helsinki, Finland.
authors.forename: S T
authors.initials: ST
authors.lastname: Jaatinen
authors.forename: L J
authors.initials: LJ
authors.lastname: Happonen
authors.forename: P
authors.initials: P
authors.lastname: Laurinmäki
authors.forename: S J
authors.initials: SJ
authors.lastname: Butcher
authors.forename: D H
authors.initials: DH
authors.lastname: Bamford
mesh_terms: D001435:Bacteriophages / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification / Q000648:ultrastructure*; D020285:Cryoelectron Microscopy; D045482:Hot Springs / Q000821:virology; D008055:Lipids / Q000032:analysis; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D017916:Tectiviridae / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification / Q000648:ultrastructure*; D016963:Thermus thermophilus / Q000821:virology*; D010948:Viral Plaque Assay; D015678:Viral Structural Proteins / Q000302:isolation & purification; D014771:Virion / Q000737:chemistry / Q000648:ultrastructure
chemical_list: D008055:Lipids; D015678:Viral Structural Proteins