Effect of cholesterol on the lateral nanoscale dynamics of fluid membranes.
Inelastic neutron scattering was used to study the effect of 5 and 40 mol% cholesterol on the lateral nanoscale dynamics of phospholipid membranes. By measuring the excitation spectrum at several lateral q                 (||) values (up to q                 (||) = 3 Å(-1)), complete dispersion curves were determined of gel, fluid and liquid-ordered phase bilayers. The inclusion of cholesterol had a distinct effect on the collective dynamics of the bilayer's hydrocarbon chains; specifically, we observed a pronounced stiffening of the membranes on the nanometer length scale in both gel and fluid bilayers, even though they were experiencing a higher degree of molecular disorder. Also, for the first time we determined the nanoscale dynamics in the high-cholesterol liquid-ordered phase of bilayers containing cholesterol. Namely, this phase appears to be "softer" than fluid bilayers, but better ordered than bilayers in the gel phase.
Department of Physics and Astronomy, McMaster University, ABB-241, 1280 Main Street West, Hamilton, ON, L8S 4M1, Canada. armstc5@mcmaster.ca
Clare L
CL
Armstrong
Matthew A
MA
Barrett
Arno
A
Hiess
Tim
T
Salditt
John
J
Katsaras
An-Chang
AC
Shi
Maikel C
MC
Rheinstädter
D002784:Cholesterol / Q000737:chemistry*; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D033363:Neutron Diffraction
D008051:Lipid Bilayers; D002784:Cholesterol; D004134:Dimyristoylphosphatidylcholine