Mapping the N-terminal residues of Epstein-Barr virus gp42 that bind gH/gL by using fluorescence polarization and cell-based fusion assays

Fengling Liu, Gaby Marquardt, Austin N. Kirschner, Richard Longnecker, Theodore S. Jardetzky

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Epstein-Barr virus (EBV) requires at a minimum membrane-associated glycoproteins gB, gH, and gL for entry into host cells. B-cell entry additionally requires gp42, which binds to gH/gL and triggers viral entry into B cells. The presence of soluble gp42 inhibits membrane fusion with epithelial cells by forming a stable heterotrimer of gH/gL/gp42. The interaction of gp42 with gH/gL has been previously mapped to residues 36 to 81 at the N-terminal region of gp42. In this study, we further mapped this region to identify essential features for binding to gH/gL by use of synthetic peptides. Data from fluorescence polarization, cell-cell fusion, and viral infection assays demonstrated that 33 residues corresponding to 44 to 61 and 67 to 81 of gp42 were indispensable for maintaining low-nanomolar-concentration gH/gL binding affinity and inhibiting B-cell fusion and epithelial cell fusion as well as viral infection. Overall, specific, large hydrophobic side chain residues of gp42 appeared to provide critical interactions, determining the binding strength. Mutations of these residues also diminished the inhibition of B-cell and epithelial cell fusions as well as EBV infection. A linker region (residues 62 to 66) between two gH/gL binding regions served as an important spacer, but individual amino acids were not critical for gH/gL binding. Probing the binding site of gH/gL and gp42 with gp42 peptides is critical for a better understanding of the interaction of gH/gL with gp42 as well as for the design of novel entry inhibitors of EBV and related human herpesviruses.

Original languageEnglish (US)
Pages (from-to)10375-10385
Number of pages11
JournalJournal of virology
Volume84
Issue number19
DOIs
StatePublished - Oct 2010

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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