Structure of the hepatitis E virus-like particle suggests mechanisms for virus assembly and receptor binding

Proc Natl Acad Sci U S A. 2009 Aug 4;106(31):12992-7. doi: 10.1073/pnas.0904848106. Epub 2009 Jul 21.

Abstract

Hepatitis E virus (HEV), a small, non-enveloped RNA virus in the family Hepeviridae, is associated with endemic and epidemic acute viral hepatitis in developing countries. Our 3.5-A structure of a HEV-like particle (VLP) shows that each capsid protein contains 3 linear domains that form distinct structural elements: S, the continuous capsid; P1, 3-fold protrusions; and P2, 2-fold spikes. The S domain adopts a jelly-roll fold commonly observed in small RNA viruses. The P1 and P2 domains both adopt beta-barrel folds. Each domain possesses a potential polysaccharide-binding site that may function in cell-receptor binding. Sugar binding to P1 at the capsid protein interface may lead to capsid disassembly and cell entry. Structural modeling indicates that native T = 3 capsid contains flat dimers, with less curvature than those of T = 1 VLP. Our findings significantly advance the understanding of HEV molecular biology and have application to the development of vaccines and antiviral medications.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Capsid Proteins / chemistry*
  • Dimerization
  • Hepatitis E virus / chemistry*
  • Hepatitis E virus / physiology
  • Models, Molecular
  • Molecular Sequence Data
  • Polysaccharides / metabolism
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Receptors, Virus / physiology*
  • Virion / chemistry*
  • Virus Assembly*

Substances

  • Capsid Proteins
  • Polysaccharides
  • Receptors, Virus

Associated data

  • PDB/3HAG