Thermal Phase Transitions in Biomembranes

Abstract

Many years ago Dayson and Danielli (1) suggested that the lipids in biological membranes are organized in a two-dimensional array, similar to the liquid-crystalline lamellar phase which phospholipids exhibit in excess water. Much of the membrane protein was assumed to be bound on each side to the polar ends of the lipid molecules. Although this bilayer concept, with minor modifications, is the most commonly accepted model for membrane structure, recently many investigators have suggested alternative arrangements which emphasize nonpolar association of lipid hydrocarbon chains with proteins (2). Some of the current speculation and divergence of opinion can be attributed to a lack of definitive experimental approaches.