Cholesterol Perturbs Lipid Bilayers Non-Universally

ORAL

Abstract

Cholesterol is well known to modulate the physical properties of biomembranes. Using modern x-ray scattering methods, we have studied the effects of cholesterol on the bending modulus K$_{C}$, the thickness D$_{HH}$, and the orientational order parameter S$_{xray}$ of lipid bilayers. We find that the effects are different for at least three classes of phospholipids characterized by different numbers of saturated hydrocarbon chains. Most strikingly, cholesterol strongly increases K$_{C}$ when both chains of the phospholipid are fully saturated but not at all when there are two mono-unsaturated chains.

*This research was supported by NIH Grant GM 44976. Synchrotron beam time was provided by CHESS, which is funded by NSF Grant DMR-0225180.

–

Authors

  • John Nagle

    • Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213
    • Dept. Biol. Sci. and Physics Dept., Carnegie Mellon University, Pittsburgh, PA
    • Carnegie Mellon University

  • Jianjun Pan

    • Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213
    • Biol. Phys. Group, Physics Dept., Carnegie Mellon University, Pittsburgh, PA

  • Thalia Mills

    • Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213

  • Stephanie Tristram-Nagle

    • Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213
    • Biol. Phys. Group, Physics Dept., Carnegie Mellon University, Pittsburgh, PA
    • Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213