The mature avian leukosis virus subgroup A envelope glycoprotein is metastable, and refolding induced by the synergistic effects of receptor binding and low pH is coupled to infection

J Virol. 2004 Feb;78(3):1403-10. doi: 10.1128/jvi.78.3.1403-1410.2004.

Abstract

The spring-loaded model stipulates that influenza virus infection is coupled to the transition of the virus hemagglutinin (HA) from a metastable conformation to a highly stable conformation at low pH. The properties of retrovirus envelope glycoproteins indicate that infection is coupled to an analogous conformational change. As a test of this hypothesis, the requirements for avian leukosis virus A (ALV-A) infection were examined. These studies indicate that, like HA, the conformation of the mature ALV-A envelope glycoprotein is metastable and that infection is linked to refolding at low pH. However, unlike HA, low-pH activation is only observed after priming by receptor. Therefore, ALV-A infection is dependent on the synergistic effects of receptor binding and low pH, suggesting that receptor binding superimposes an additional constraint on activation of ALV-A fusion that proceeds by a mechanism comparable to that of influenza virus.

Publication types

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

MeSH terms

  • Animals
  • Avian Leukosis Virus / pathogenicity*
  • Avian Proteins
  • Cell Line
  • Cell Membrane / metabolism
  • Humans
  • Hydrogen-Ion Concentration
  • Membrane Fusion
  • Protein Conformation
  • Protein Folding*
  • Receptors, Virus / metabolism*
  • Solubility
  • Viral Envelope Proteins / chemistry*
  • Viral Envelope Proteins / metabolism

Substances

  • Avian Proteins
  • Receptors, Virus
  • Rous sarcoma virus envelope protein gp37
  • Tva receptor
  • Viral Envelope Proteins