Effect of the Gel-Liquid Crystal Transition on the Lipid-Preference of Protein in Lipid Bilayer Membranes

Abstract

A theoretical model of lipid bilayers including a protein is presented to make clear how far from the protein the perturbation of the conformation and packing of lipid molecules due to the protein extends and what factors control the extent. The conformation and packing of lipid molecules under the presence of inter-molecular interactions are described effectively on the basis of the isomeric bond rotation scheme for free polymer chains and of the hard disk models respectively. When the boundary lipid chains have less gauche bonds than the bulk lipids, the perturbation decays smoothly in the bilayer. The perturbation does not propagate into the bilayer, when the boundary lipids are packed more roughly than the bulk lipids. The number of gauche bonds and the number density of bulk lipid molecules are changed drastically by the gell-liquid crystal phase transition. Therefore, the phase transition affects essentially the propagation of the perturbation due to the protein.