Barotropic Phase Transitions of Asymmetric Phospholipid Bilayer Membranes: Molecular Asymmetry and Phase Stability

Abstract

  The effect of pressure on the bilayer phase transitions of two kinds of asymmetric phospholipids, phosphatidylcholines (PCs) with different saturated acyl chains in the sn-1 and sn-2 positions on the glycerol backbone and mixed-chain PCs with an unsaturated acyl chain in the sn-1 or sn-2 position, is described. The alignment of the sn-1 and sn-2 acyl chains at the therminal methyl ends and the mismatch of the effective chain length between the sn-1 and sn-2 acyl chains produce a significant influence on their bilayer properties. The correlation between molecular asymmetry of PC molecules and phase stabilities of the bilayer membranes is discussed.