Flexibility and intrinsic disorder are conserved features of hepatitis C virus E2 glycoprotein

PLoS Comput Biol. 2020 Feb 28;16(2):e1007710. doi: 10.1371/journal.pcbi.1007710. eCollection 2020 Feb.

Abstract

The glycoproteins of hepatitis C virus, E1E2, are unlike any other viral fusion machinery yet described, and are the current focus of immunogen design in HCV vaccine development; thus, making E1E2 both scientifically and medically important. We used pre-existing, but fragmentary, structures to model a complete ectodomain of the major glycoprotein E2 from three strains of HCV. We then performed molecular dynamic simulations to explore the conformational landscape of E2, revealing a number of important features. Despite high sequence divergence, and subtle differences in the models, E2 from different strains behave similarly, possessing a stable core flanked by highly flexible regions, some of which perform essential functions such as receptor binding. Comparison with sequence data suggest that this consistent behaviour is conferred by a network of conserved residues that act as hinge and anchor points throughout E2. The variable regions (HVR-1, HVR-2 and VR-3) exhibit particularly high flexibility, and bioinformatic analysis suggests that HVR-1 is a putative intrinsically disordered protein region. Dynamic cross-correlation analyses demonstrate intramolecular communication and suggest that specific regions, such as HVR-1, can exert influence throughout E2. To support our computational approach we performed small-angle X-ray scattering with purified E2 ectodomain; this data was consistent with our MD experiments, suggesting a compact globular core with peripheral flexible regions. This work captures the dynamic behaviour of E2 and has direct relevance to the interaction of HCV with cell-surface receptors and neutralising antibodies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Neutralizing / immunology
  • Antibodies, Viral / immunology
  • Computer Simulation
  • Epitopes / immunology
  • Glycosylation
  • HEK293 Cells
  • Hepatitis C / virology*
  • Humans
  • Molecular Dynamics Simulation
  • Protein Binding
  • Protein Domains
  • Scattering, Radiation
  • Viral Envelope Proteins / chemistry*
  • Virus Internalization*
  • X-Rays

Substances

  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Epitopes
  • Viral Envelope Proteins
  • glycoprotein E2, Hepatitis C virus