title: Nucleocapsid and glycoprotein organization in an enveloped virus.
abstract: Alphaviruses are a group of icosahedral, positive-strand RNA, enveloped viruses. The membrane bilayer, which surrounds the approximately 400 A diameter nucleocapsid, is penetrated by 80 spikes arranged in a T = 4 lattice. Each spike is a trimer of heterodimers consisting of glycoproteins E1 and E2. Cryoelectron microscopy and image reconstruction of Ross River virus showed that the T = 4 quaternary structure of the nucleocapsid consists of pentamer and hexamer clusters of the capsid protein, but not dimers, as have been observed in several crystallographic studies. The E1-E2 heterodimers form one-to-one associations with the nucleocapsid monomers across the lipid bilayer. Knowledge of the atomic structure of the capsid protein and our reconstruction allows us to identify capsid-protein residues that interact with the RNA, the glycoproteins, and adjacent capsid-proteins.
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907.
authors.forename: R H
authors.initials: RH
authors.lastname: Cheng
authors.forename: R J
authors.initials: RJ
authors.lastname: Kuhn
authors.forename: N H
authors.initials: NH
authors.lastname: Olson
authors.forename: M G
authors.initials: MG
authors.lastname: Rossmann
authors.forename: H K
authors.initials: HK
authors.lastname: Choi
authors.forename: T J
authors.initials: TJ
authors.lastname: Smith
authors.forename: T S
authors.initials: TS
authors.lastname: Baker
mesh_terms: D005615:Freezing; D006023:Glycoproteins / Q000648:ultrastructure*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008854:Microscopy, Electron / Q000379:methods; D008961:Models, Structural; D012398:Ross River virus / Q000648:ultrastructure*; D014764:Viral Proteins / Q000648:ultrastructure*
chemical_list: D006023:Glycoproteins; D014764:Viral Proteins