title: Acidianus filamentous virus 1 coat proteins display a helical fold spanning the filamentous archaeal viruses lineage.
abstract: Acidianus filamentous virus 1 (AFV1), a member of the Lipothrixviridae family, infects the hyperthermophilic, acidophilic crenarchaeaon Acidianus hospitalis. The virion, covered with a lipidic outer shell, is 9,100-A long and contains a 20.8-kb linear dsDNA genome. We have identified the two major coat proteins of the virion (MCPs; 132 and 140 amino acids). They bind DNA and form filaments when incubated with linear dsDNA. A C-terminal domain is identified in their crystal structure with a four-helix-bundle fold. In the topological model of the virion filament core, the genomic dsDNA superhelix wraps around the AFV1-132 basic protein, and the AFV1-140 basic N terminus binds genomic DNA, while its lipophilic C-terminal domain is imbedded in the lipidic outer shell. The four-helix bundle fold of the MCPs from AFV1 is identical to that of the coat protein (CP) of Sulfolobus islandicus rod-shaped virus (SIRV), a member of the Rudiviridae family. Despite low sequence identity between these proteins, their high degree of structural similarity suggests that they could have derived from a common ancestor and could thus define an yet undescribed viral lineage.
authors.affiliation: Architecture et Fonction des Macromolécules Biologiques, Centre national de la Recherche Scientifique and Universités Aix-Marseille I & II, Architecture et Fonction des Macromolécules Biologiques, Unité Mixte de Recherche 6098, Case 932, 163 avenue de Luminy, 13288 Marseille Cedex 9, France.
authors.forename: Adeline
authors.initials: A
authors.lastname: Goulet
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Blangy
authors.forename: Peter
authors.initials: P
authors.lastname: Redder
authors.forename: David
authors.initials: D
authors.lastname: Prangishvili
authors.forename: Catarina
authors.initials: C
authors.lastname: Felisberto-Rodrigues
authors.forename: Patrick
authors.initials: P
authors.lastname: Forterre
authors.forename: Valérie
authors.initials: V
authors.lastname: Campanacci
authors.forename: Christian
authors.initials: C
authors.lastname: Cambillau
mesh_terms: D041541:Acidianus / Q000821:virology; D036022:Capsid Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry; D016679:Genome, Viral; D023643:Lipothrixviridae / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D017510:Protein Folding; D017433:Protein Structure, Secondary; D040681:Structural Homology, Protein; D016944:Sulfolobus / Q000737:chemistry
chemical_list: D036022:Capsid Proteins; D004268:DNA-Binding Proteins