Nucleocapsid and glycoprotein organization in an enveloped virus.
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.
Cheng
R H
RH
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907.
Kuhn
R J
RJ
Olson
N H
NH
Rossmann
M G
MG
Choi
H K
HK
Smith
T J
TJ
Baker
T S
TS
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*
D006023:Glycoproteins; D014764:Viral Proteins