Structural determinants of rotavirus subgroup specificity mapped by cryo-electron microscopy

J Mol Biol. 2006 Feb 10;356(1):209-21. doi: 10.1016/j.jmb.2005.11.049. Epub 2005 Dec 1.


The rotavirus double-layered particle (DLP) is a molecular machine that transcribes 11 genomic segments of double-stranded RNA into full-length mRNA segments during viral replication. DLPs from the human Wa strain of virus, belonging to subgroup II (SG II), possess a significantly reduced level of transcriptase activity compared to bovine UK DLPs that belong to subgroup I (SG I). Cryo-electron microscopy and icosahedral image analysis was used to define the structural basis for this difference in transcriptase activity and to derive three-dimensional density maps of bovine UK and human Wa DLPs at 26 angstroms and 28 angstroms resolution, respectively. The two rotavirus strains had the same diameter, T = 13 l icosahedral lattice symmetry and size of the VP6 trimers on the surface of the DLPs. However, the Wa particles displayed a remarkable absence of VP6 trimers surrounding each 5-fold vertex position. To further explore these structural differences, three-dimensional reconstructions were generated of DLPs decorated with Fab fragments derived from subgroup-specific monoclonal antibodies. The X-ray structures of VP6 and a generic Fab fragment were then docked into the cryo-electron microscopy density maps, which allowed us to propose at "pseudo-atomic" resolution the locations of the amino acid residues defining the subgroup-specific epitopes. Our results demonstrate a correlation between the structure of the VP6 layer and the transcriptase activity of the particles, and suggest that the stability of VP6 trimers, specifically those at the icosahedral 5-fold axes, may be critical for mRNA synthesis. Thus, subgroup specificity of rotavirus may reflect differences in the architecture of the double-layered particle, with resultant consequences for viral mRNA synthesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal / immunology
  • Antibodies, Viral / immunology
  • Binding Sites
  • Cattle
  • Cryoelectron Microscopy*
  • Epitopes / immunology
  • Humans
  • Models, Molecular
  • Protein Binding
  • Protein Structure, Quaternary
  • RNA-Directed DNA Polymerase / metabolism
  • Rotavirus / chemistry
  • Rotavirus / classification*
  • Rotavirus / ultrastructure*
  • Viral Proteins / chemistry
  • Viral Proteins / classification
  • Viral Proteins / ultrastructure
  • Virion / chemistry
  • Virion / ultrastructure


  • Antibodies, Monoclonal
  • Antibodies, Viral
  • Epitopes
  • Viral Proteins
  • RNA-Directed DNA Polymerase