Two-Dimensional Ordering of Bacteriorhodopsins in a Lipid Bilayer and Effects Caused by Repulsive Core between Lipid Molecules on Lateral Depletion Interaction: A Study based on a Thermodynamic Perturbation Theory

TL;DR

This study uses thermodynamic perturbation theory on binary hard disk models to analyze how repulsive interactions between lipids influence the ordering and phase behavior of bacteriorhodopsins in lipid bilayers.

Contribution

It introduces a detailed analysis of lateral depletion effects caused by lipid core repulsions on membrane protein ordering using a thermodynamic perturbation approach.

Findings

Core repulsions significantly expand the fluid-ordered phase coexistence region.

Lateral depletion effects are strongly influenced by lipid core interactions.

Phase diagrams reveal the impact of lipid interactions on membrane organization.

Abstract

Using binary hard disk mixture models, we studied the two-dimensional ordering of bacteriorhodopsins in a lipid bilayer. The phase diagrams were calculated using the thermodynamic perturbation theory. We examined two types of effective interactions to discuss the lateral depletion effects caused by repulsive core interaction between lipid molecules. The results indicate that the core repulsions drastically broaden the coexistence region for the fluid--ordered phase.