title: An icosahedral algal virus has a complex unique vertex decorated by a spike.
abstract: Paramecium bursaria Chlorella virus-1 is an icosahedrally shaped, 1,900-A-diameter virus that infects unicellular eukaryotic green algae. A 5-fold symmetric, 3D reconstruction using cryoelectron microscopy images has now shown that the quasiicosahedral virus has a unique vertex, with a pocket on the inside and a spike structure on the outside of the capsid. The pocket might contain enzymes for use in the initial stages of infection. The unique vertex consists of virally coded proteins, some of which have been identified. Comparison of shape, size, and location of the spike with similar features in bacteriophages T4 and P22 suggests that the spike might be a cell-puncturing device. Similar asymmetric features may have been missed in previous analyses of many other viruses that had been assumed to be perfectly icosahedral.
authors.affiliation: Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907-2054, USA.
authors.forename: Mickaël V
authors.initials: MV
authors.lastname: Cherrier
authors.forename: Victor A
authors.initials: VA
authors.lastname: Kostyuchenko
authors.forename: Chuan
authors.initials: C
authors.lastname: Xiao
authors.forename: Valorie D
authors.initials: VD
authors.lastname: Bowman
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Battisti
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Yan
authors.forename: Paul R
authors.initials: PR
authors.lastname: Chipman
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Baker
authors.forename: James L
authors.initials: JL
authors.lastname: Van Etten
authors.forename: Michael G
authors.initials: MG
authors.lastname: Rossmann
mesh_terms: D002213:Capsid / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D017862:Phycodnaviridae / Q000648:ultrastructure*