High-resolution cryo-EM structures of outbreak strain human norovirus shells reveal size variations

Proc Natl Acad Sci U S A. 2019 Jun 25;116(26):12828-12832. doi: 10.1073/pnas.1903562116. Epub 2019 Jun 10.


Noroviruses are a leading cause of foodborne illnesses worldwide. Although GII.4 strains have been responsible for most norovirus outbreaks, the assembled virus shell structures have been available in detail for only a single strain (GI.1). We present high-resolution (2.6- to 4.1-Å) cryoelectron microscopy (cryo-EM) structures of GII.4, GII.2, GI.7, and GI.1 human norovirus outbreak strain virus-like particles (VLPs). Although norovirus VLPs have been thought to exist in a single-sized assembly, our structures reveal polymorphism between and within genogroups, with small, medium, and large particle sizes observed. Using asymmetric reconstruction, we were able to resolve a Zn2+ metal ion adjacent to the coreceptor binding site, which affected the structural stability of the shell. Our structures serve as valuable templates for facilitating vaccine formulations.

Keywords: cryo-EM; foodborne illnesses; norovirus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caliciviridae Infections / virology
  • Capsid / metabolism
  • Capsid / ultrastructure*
  • Cryoelectron Microscopy
  • Disease Outbreaks*
  • Genetic Variation
  • Humans
  • Norovirus / genetics
  • Norovirus / isolation & purification
  • Norovirus / ultrastructure*
  • Protein Binding
  • Zinc / metabolism


  • Zinc

Associated data

  • PDB/6OUT
  • PDB/6OU9
  • PDB/6OTF
  • PDB/6OUC
  • PDB/6OUU