Differential Modulation of Membrane Structure and Fluctuations By Plant Sterols and Cholesterol

Posted on: Friday, 25 July 2008, 03:00 CDT By Hodzic, Aden Rappolt, Michael; Amenitsch, Heinz; Laggner, Peter; Pabst, Georg ABSTRACT We have studied the concentration and temperature dependent influence of cholesterol, stigmasterol, and sitosterol on the global structure and the bending fluctuations of fluid dimyristoyl phosphatidylcholine and palmitoyl oleoyl phosphatidylcholine bilayers applying small-angle x-ray scattering, as well as dilatometry and ultrasound velocimetry. Independent of the lipid matrix, cholesterol was found to be most efficient in modulating bilayer thickness and elasticity, followed by sitosterol and stigmasterol. This can be attributed to the additional ethyl groups and double bond at the C^sub 17^ alkyl side-chain of the two plant sterols. Hence, it seems that some flexibility of the sterol... [read full story]