Refolding of a paramyxovirus F protein from prefusion to postfusion conformations observed by liposome binding and electron microscopy

Sarah A. Connolly, George P. Leser, Hsien Shen Yin, Theodore S. Jardetzky, Robert A. Lamb*

*Corresponding author for this work

Research output: Contribution to journalArticle

73 Scopus citations

Abstract

For paramyxoviruses, two viral glycoproteins are key to the entry process: an attachment protein (HN, H, or G) and the fusion protein (F). The F protein folds to a metastable state that can be triggered to undergo large conformational rearrangements to a fusogenic intermediate and a more stable postfusion state. The triggering mechanism that controls paramyxovirus fusion has not been elucidated. To correlate the molecular structure of a soluble form of the prefusion F (PIV5 F-GCNt) with the biological function of F, soluble F protein was triggered to refold. In the absence of HN, heat was found to function as a surrogate F trigger, and F associated with liposomes and aggregated on sucrose density gradients. Electron microscopy data showed that triggered F formed rosettes. Taken together these data suggest that release and membrane insertion of the hydrophobic fusion peptide require both cleavage of F and heat. Heating of cleaved F causes conversion to a postfusion form as judged by its "golf tee" morphology in the electron microscope. Heating of uncleaved F also causes conversion of F to a morphologically similar form. The reactivity of the F protein with conformation-specific mAbs and peptide binding suggest that soluble F-GCNt and membrane-bound F proteins refold through a comparable pathway.

Original languageEnglish (US)
Pages (from-to)17903-17908
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume103
Issue number47
DOIs
StatePublished - Nov 21 2006

Keywords

  • Conformational change
  • Fusion peptide
  • Metastable
  • Trigger

ASJC Scopus subject areas

  • General

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