Structural Properties of a Lecithin-Cholesterol System: Ripple Structure and Phase Diagram

Abstract

Cholesterol is an amphipathic lipid molecule which occurs as a major component of cellular membranes and of lipoproteins. In plasma membranes, the ratio of cholesterol to the other plasma membrane lipids, phospholipids etc. is about 0.7–0.8 mol/mol, whereas in intracellular membranes it is typically 0.1–0.2 mol/mol. Cholesterol serves as a precursor for various acids and hormones, however, it has also major influence on the membrane function and structure itself. Numerous studies have been performed during the last decades in order to learn about the role of cholesterol^1,2. But still there is a severe difference of opinion on basic issues such as the location of the cholesterol in the cell membranes and how cholesterol affects various structural features^3,4.