title: Insight into the Assembly of Viruses with Vertical Single β-barrel Major Capsid Proteins.
abstract: Archaeal viruses constitute the least explored niche within the virosphere. Structure-based approaches have revealed close relationships between viruses infecting organisms from different domains of life. Here, using biochemical and cryo-electron microscopy techniques, we solved the structure of euryarchaeal, halophilic, internal membrane-containing Haloarcula hispanica icosahedral virus 2 (HHIV-2). We show that the density of the two major capsid proteins (MCPs) recapitulates vertical single β-barrel proteins and that disulfide bridges stabilize the capsid. Below, ordered density is visible close to the membrane and at the five-fold vertices underneath the host-interacting vertex complex underpinning membrane-protein interactions. The HHIV-2 structure exemplifies the division of conserved architectural elements of a virion, such as the capsid, from those that evolve rapidly due to selective environmental pressure such as host-recognizing structures. We propose that in viruses with two vertical single β-barrel MCPs the vesicle is indispensable, and membrane-protein interactions serve as protein-railings for guiding the assembly.
authors: Structural Biology Unit, CIC bioGUNE, CIBERehd, Bizkaia Technology Park, 48160 Derio, Spain.
authors: David
authors: D
authors: Gil-Carton
authors: Department of Biosciences and Institute of Biotechnology, Viikki Biocenter, University of Helsinki, P.O. Box 56, Viikinkaari 9, 00014 Helsinki, Finland.
authors: Salla T
authors: ST
authors: Jaakkola
authors: Structural Biology Unit, CIC bioGUNE, CIBERehd, Bizkaia Technology Park, 48160 Derio, Spain.
authors: Diego
authors: D
authors: Charro
authors: Structural Biology Unit, CIC bioGUNE, CIBERehd, Bizkaia Technology Park, 48160 Derio, Spain.
authors: Bibiana
authors: B
authors: Peralta
authors: Scientific Computing Unit, Max-Planck Institute for Brain Research, 60438 Frankfurt, Germany.
authors: Daniel
authors: D
authors: Castaño-Díez
authors: Department of Biosciences and Institute of Biotechnology, Viikki Biocenter, University of Helsinki, P.O. Box 56, Viikinkaari 9, 00014 Helsinki, Finland.
authors: Hanna M
authors: HM
authors: Oksanen
authors: Department of Biosciences and Institute of Biotechnology, Viikki Biocenter, University of Helsinki, P.O. Box 56, Viikinkaari 9, 00014 Helsinki, Finland.
authors: Dennis H
authors: DH
authors: Bamford
authors: Structural Biology Unit, CIC bioGUNE, CIBERehd, Bizkaia Technology Park, 48160 Derio, Spain; IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain. Electronic address: nabrescia@cicbiogune.es.
authors: Nicola G A
authors: NGA
authors: Abrescia
mesh_terms: D023641:Archaeal Viruses / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D001665:Binding Sites; D002213:Capsid / Q000378:metabolism / Q000648:ultrastructure*; D036022:Capsid Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D004220:Disulfides; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D016679:Genome, Viral; D019613:Haloarcula / Q000821:virology; D008958:Models, Molecular; D011485:Protein Binding; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055049:Salt Tolerance; D014771:Virion / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D019065:Virus Assembly
chemical_list: D036022:Capsid Proteins; D004220:Disulfides; D011994:Recombinant Proteins