title: Three-dimensional reconstruction of Heterocapsa circularisquama RNA virus by electron cryo-microscopy.
abstract: Heterocapsa circularisquama RNA virus is a non-enveloped icosahedral ssRNA virus infectious to the harmful bloom-forming dinoflagellate, H. circularisquama, and which is assumed to be the major natural agent controlling the host population. The viral capsid is constructed from a single gene product. Electron cryo-microscopy revealed that the virus has a diameter of 34 nm and T = 3 symmetry. The 180 quasi-equivalent monomers have an unusual arrangement in that each monomer contributes to a 'bump' on the surface of the protein. Though the capsid protein probably has the classic 'jelly roll' β-sandwich fold, this is a new packing arrangement and is distantly related to the other positive-sense ssRNA virus capsid proteins. The handedness of the structure has been determined by a novel method involving high resolution scanning electron microscopy of the negatively stained viruses and secondary electron detection.
authors.affiliation: Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Miller
authors.affiliation: Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Woodward
authors.affiliation: MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
authors.forename: Shaoxia
authors.initials: S
authors.lastname: Chen
authors.affiliation: Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Jaffer
authors.affiliation: Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa.
authors.forename: Brandon
authors.initials: B
authors.lastname: Weber
authors.affiliation: National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, Hiroshima 739-0452, Japan.
authors.forename: Keizo
authors.initials: K
authors.lastname: Nagasaki
authors.affiliation: National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, Hiroshima 739-0452, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tomaru
authors.affiliation: Electron Microscopy ETH Zurich (EMEZ), 8093 Zurich, Switzerland.
authors.forename: Roger
authors.initials: R
authors.lastname: Wepf
authors.affiliation: Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Roseman
authors.affiliation: School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.|Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand.|Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa.
authors.forename: Arvind
authors.initials: A
authors.lastname: Varsani
authors.affiliation: Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa.
authors.forename: Trevor
authors.initials: T
authors.lastname: Sewell
mesh_terms: D002213:Capsid / Q000737:chemistry / Q000648:ultrastructure; D020285:Cryoelectron Microscopy / Q000379:methods*; D004141:Dinoflagellida / Q000821:virology; D007091:Image Processing, Computer-Assisted; D011487:Protein Conformation; D012328:RNA Viruses / Q000737:chemistry / Q000302:isolation & purification / Q000648:ultrastructure*; D013499:Surface Properties