Cholesterol slows down the lateral mobility of an oxidized phospholipid in a supported lipid bilayer

Langmuir. 2010 Nov 16;26(22):17322-9. doi: 10.1021/la1026202. Epub 2010 Oct 13.

Abstract

We investigated the mobility and phase-partitioning of the fluorescent oxidized phospholipid analogue 1-palmitoyl-2-glutaroyl-sn-glycero-3-phospho-N-Alexa647-ethanolamine (PGPE-Alexa647) in supported lipid bilayers. Compared to the conventional phospholipid dihexadecanoylphosphoethanolamine (DHPE)-Bodipy we found consistently higher diffusion constants. The effect became dramatic when immobile obstacles were inserted into the bilayer, which essentially blocked the diffusion of DHPE-Bodipy but hardly influenced the movements of PGPE-Alexa647. In a supported lipid bilayer made of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), the differences in probe mobility leveled off with increasing cholesterol content. Using coarse-grained molecular dynamics simulations, we could ascribe this effect to increased interactions between the oxidized phospholipid and the membrane matrix, concomitant with a translation in the headgroup position of the oxidized phospholipid: at zero cholesterol content, its headgroup is shifted to the outside of the DOPC headgroup region, whereas increasing cholesterol concentrations pulls the headgroup into the bilayer plane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cholesterol / chemistry
  • Cholesterol / metabolism*
  • Diffusion
  • Ethanolamines / chemistry
  • Kinetics
  • Lipid Bilayers / chemistry*
  • Lipid Bilayers / metabolism*
  • Molecular Conformation
  • Molecular Dynamics Simulation
  • Movement*
  • Oxidation-Reduction
  • Phospholipids / chemistry
  • Phospholipids / metabolism*

Substances

  • Ethanolamines
  • Lipid Bilayers
  • Phospholipids
  • Cholesterol