Phase transitions between ripple structures in hydrated phosphatidylcholine-cholesterol multilamellar assemblies

Abstract

A dynamic thermally induced cooperative first-order phase transition between ripple phases is described for fully hydrated mixtures of dipalmitoylphosphatidylcholine and 5-mole % cholesterol bilayers. The ripple-ripple phase transition has not been observed for pure phosphatidylcholine systems. This transition has not been observed for pure phosphatidylcholine systems. This transition is more likely driven by changes in headgroup-water-headgroup interactions than by a change in acyl chain tilt. Implications for mechanical processes within a lipid bilayer are discussed.