Membrane mediated regulation in free peptides of HIV-1 gp41: minimal modulation of the hemifusion phase

Eleonora Cerasoli, Jascindra Ravi, Craig Gregor, Rohanah Hussain, Giuliano Siligardi, Glenn Martyna, Jason Crain, Maxim G. Ryadnov

Research output: Contribution to journalArticlepeer-review

Abstract

Membrane-mediated structural modulation in two short fragments of the human HIV-1 envelope protein gp41 is demonstrated. Derived from the C-terminal membrane proximal external (MPE) and N-terminal fusion peptide proximal (FPP) regions, these peptides are widely separated in the primary sequence but form tertiary contacts during the intermediate (hemifusion) phase of HIV infection. The structural perturbations observed at the membrane interface offer evidence of rudimentary regulatory mechanisms operating in the free peptides which may be relevant in the biological system. No such regulatory phenomena were observed for the individual peptides in a membrane environment or between the peptides in aqueous solutions. Structure determination is made using a combination of circular and linear dichroism spectroscopy (supported by calorimetric measurements) and molecular dynamics simulations. Specifically, we show that these peptides interact locally without the conformational support of helical heptad repeat regions in native gp41 and that the modulation is not mutual with the FPP peptide operating as a primary regulator of the MPE-FPP interactions in the hemifusion phase.

Original languageEnglish
Pages (from-to)1277-1285
Number of pages9
JournalPhysical Chemistry Chemical Physics
Volume14
Issue number3
DOIs
Publication statusPublished - 21 Jan 2012

Keywords

  • MOLECULAR-DYNAMICS
  • SECONDARY-STRUCTURE
  • FUSION PEPTIDE
  • NEUTRALIZING ANTIBODIES
  • LINEAR DICHROISM
  • ENTRY INHIBITOR
  • COUETTE-FLOW
  • MODEL
  • PROTEIN
  • EPITOPE

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