Studies on the Structure of the Influenza Virus Haemagglutinin at the pH of Membrane Fusion
- 1 November 1988
- journal article
- research article
- Published by Microbiology Society in Journal of General Virology
- Vol. 69 (11), 2785-2795
- https://doi.org/10.1099/0022-1317-69-11-2785
Abstract
At the pH required to trigger the membrane fusion activity of the influenza virus haemagglutinin (HA) the soluble ectodomain of the molecule, BHA, which is released from virus by bromelain digestion, aggregates into rosettes. Analyses of soluble proteolytic fragments derived from the rosettes indicated that aggregation is mediated by association of the conserved hydrophobic amino-terminal region of BHA2, the smaller glycopolypeptide component of each BHA subunit. Further analyses of the structure of the soluble fragments and of HA in its low pH conformation by electron microscopy, spectroscopy and in crosslinking experiments showed that, although the membrane distal globular domains lose their trimer structure at the pH of fusion, the central fibrous stem of the molecule remains trimeric and assumes a more stable conformation. The increase in length of BHA2 at low pH observed microscopically appears to result from movement of the amino-terminal region to the membrane proximal end of the molecule and in virus incubated at low pH the amino terminus may insert into the virus membrane. The consequences of these possibilities for the mechanism of membrane fusion are discussed.This publication has 16 references indexed in Scilit:
- Electron microscopy of the low pH structure of influenza virus haemagglutinin.The EMBO Journal, 1986
- Antigenic Determinants of Influenza Virus Haemagglutinin. X. A Comparison of the Physical and Antigenic Properties of Monomeric and Trimeric FormsJournal of General Virology, 1985
- Electron microscopy of influenza virusJournal of Molecular Biology, 1985
- Fusion mutants of the influenza virus hemagglutinin glycoproteinCell, 1985
- MEMBRANE-FUSION ACTIVITY OF THE INFLUENZA-VIRUS HEMAGGLUTININ - THE LOW PH-INDUCED CONFORMATIONAL CHANGE1985
- Combining accurate defocus with low-dose imaging in high resolution electron microscopy of biological materialJournal of Microscopy, 1983
- Changes in the conformation of influenza virus hemagglutinin at the pH optimum of virus-mediated membrane fusion.Proceedings of the National Academy of Sciences, 1982
- Interaction of influenza virus hemagglutinin with target membrane lipids is a key step in virus-induced hemolysis and fusion at pH 5.2.Proceedings of the National Academy of Sciences, 1981
- Structure of the haemagglutinin membrane glycoprotein of influenza virus at 3 Å resolutionNature, 1981
- Evidence from studies with a cross-linking reagent that the haemagglutinin of influenza virus is a trimerVirology, 1977