Dresden 2006 – scientific programme
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AKB: Biologische Physik
AKB 40: Poster Session II
AKB 40.36: Poster
Wednesday, March 29, 2006, 16:30–19:30, P3
Effect of cholesterol on the collective dynamics ofphospholipid membranes — •Beate Brüning1,2, Tim Salditt2, Arno Hiess1, and Maikel C. Rheinstädter1 — 1Institut Laue-Langevin,B.P. 156,6 rue JulesHorowitz,38042 Grenoble,France — 2Institut für Röntgenphysik,Friedrich-Hund-Platz1,37077 Göttingen,Germany
Phospholipid membranes often serve as simple model systems to understand basic properties of their far more complex biological counterparts. Only recently, the collective short wavelength dynamics in a model membrane system (DMPC), i.e., the corresponding dispersion relation, were investigated by inelastic neutron scattering techniques [1]. The insertion of the membrane-active molecule cholesterol, which is known to regulate membrane fluidity, membrane permeability and the lateral mobility of proteins, is now a first step towards the understanding of coherent dynamics in physiologically relevant membrane systems.
While the structure of phospholipid/cholesterol systems is well studied, their short scale dynamics are so far largely unknown. We have studied the influence of cholesterol to the collective short wavelength fluctuations of the phospholipid acyl chains using inelastic neutron scattering. The measurements were carried out with thermal as well as cold neutrons on the three-axis spectrometers IN12 and IN8 at the high flux reactor of the ILL in Grenoble, France. We were able to determine the dispersion relations within the plane of the membranes in the fluid and the liquid ordered phases of samples with two different cholesterol contents, namely 3% and 35%.
[1] M.C. Rheinstädter et al., Phys. Rev. Lett. 93, 108107 (2004).