The kinetics of non-lamellar phase formation in DOPE-Me: relevance to biomembrane fusion

J Membr Biol. 2003 Oct 1;195(3):165-82. doi: 10.1007/s00232-003-0617-z.

Abstract

The mechanism of the lamellar/inverted cubic (QII) phase transition is related to that of membrane fusion in lipid systems. N-Monomethylated dioleoylphosphatidylethanolamine (DOPE-Me) exhibits this transition and is commonly used to investigate the effects of exogenous substances, such as viral fusion peptides, on the mechanism of membrane fusion. We studied DOPE-Me phase behavior as a first step in evaluating the effects of membrane-spanning peptides on inverted phase formation and membrane fusion. These measurements show that: a) the onset temperatures for QII and inverted hexagonal (HII) phase formation both are temperature scan rate-dependent; b) longer pre-incubation times at low temperature and lower temperature scan rates favor formation of the QII phase; and c) in temperature-jump experiments between 61 and 65 degrees C, the meta-stable HII phase forms initially, and disappears slowly while the QII phase develops. These observations are rationalized in the context of a mechanism for both the lamellar/non-lamellar phase transition and the related process of membrane fusion.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Calorimetry, Differential Scanning
  • Chromatography, Thin Layer
  • Kinetics
  • Lipid Bilayers / chemistry*
  • Liposomes / chemistry
  • Membrane Fusion*
  • Micelles
  • Models, Molecular
  • Phase Transition*
  • Phosphatidylethanolamines / chemistry*
  • X-Ray Diffraction

Substances

  • Lipid Bilayers
  • Liposomes
  • Micelles
  • Phosphatidylethanolamines