Capture and imaging of a prehairpin fusion intermediate of the paramyxovirus PIV5

Yong Ho Kim, Jason E. Donald, Gevorg Grigoryan, George P. Leser, Alexander Y. Fadeev, Robert A Lamb*, William F. DeGrado

*Corresponding author for this work

Research output: Contribution to journalArticle

43 Scopus citations

Abstract

During cell entry, enveloped viruses fuse their viral membrane with a cellular membrane in a process driven by energetically favorable, large-scale conformational rearrangements of their fusion proteins. Structures of the pre- and postfusion states of the fusion proteins including paramyxovirus PIV5 F and influenza virus hemagglutinin suggest that this occurs via two intermediates. Following formation of an initial complex, the proteins structurally elongate, driving a hydrophobic N-terminal "fusion peptide" away from the protein surface into the target membrane. Paradoxically, this first conformation change moves the viral and cellular bilayers further apart. Next, the fusion proteins form a hairpin that drives the two membranes into close opposition.While the pre- and post-fusion hairpin forms have been characterized crystallographically, the transiently extended prehairpin intermediate has not been visualized. To provide evidence for this extended intermediate we measured the interbilayer spacing of a paramyxovirus trapped in the process of fusing with solid-supported bilayers. A gold-labeled peptide that binds the prehairpin intermediate was used to stabilize and specifically image F-proteins in the prehairpin intermediate. The interbilayer spacing is precisely that predicted from a computational model of the prehairpin, providing strong evidence for its structure and functional role. Moreover, the F-proteins in the prehairpin conformation preferentially localize to a patch between the target and viral membranes, consistent with the fact that the formation of the prehairpin is triggered by local contacts between F- and neighboring viral receptor-binding proteins (HN) only when HN binds lipids in its target membrane.

Original languageEnglish (US)
Pages (from-to)20992-20997
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number52
DOIs
StatePublished - Dec 27 2011

Keywords

  • Electron microscopy
  • Fusion protein refolding
  • Membrane fusion

ASJC Scopus subject areas

  • General

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