Nucleocapsid and glycoprotein organization in an enveloped virus

Cell. 1995 Feb 24;80(4):621-30. doi: 10.1016/0092-8674(95)90516-2.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Freezing
  • Glycoproteins / ultrastructure*
  • Image Processing, Computer-Assisted / methods
  • Microscopy, Electron / methods
  • Models, Structural
  • Ross River virus / ultrastructure*
  • Viral Proteins / ultrastructure*


  • Glycoproteins
  • Viral Proteins