In Vitro reconstitution reveals key intermediate states of trimer formation by the dengue virus membrane fusion protein

Maofu Liao, Claudia Sánchez-San Martín, Aihua Zheng, Margaret Kielian

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

The flavivirus dengue virus (DV) infects cells through a low-pH-triggered membrane fusion reaction mediated by the viral envelope protein E. E is an elongated transmembrane protein with three domains and is organized as a homodimer on the mature virus particle. During fusion, the E protein homodimer dissociates, inserts the hydrophobic fusion loop into target membranes, and refolds into a trimeric hairpin in which domain III (DIII) packs against the central trimer. It is clear that E refolding drives membrane fusion, but the steps in hairpin formation and their pH requirements are unclear. Here, we have used truncated forms of the DV E protein to reconstitute trimerization in vitro. Protein constructs containing domains I and II (DI/II) were monomeric and interacted with membranes to form core trimers. DI/II-membrane interaction and trimerization occurred efficiently at both neutral and low pH. The DI/II core trimer was relatively unstable and could be stabilized by binding exogenous DIII or by the formation of mixed trimers containing DI/II plus E protein with all three domains. The mixed trimer had unoccupied DIII interaction sites that could specifically bind exogenous DIII at either low or neutral pH. Truncated DV E proteins thus reconstitute hairpin formation and define properties of key domain interactions during DV fusion.

Original languageEnglish (US)
Pages (from-to)5730-5740
Number of pages11
JournalJournal of virology
Volume84
Issue number11
DOIs
StatePublished - Jun 1 2010

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ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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