Statistical Mechanics of Membrane Protein Conformation: A Homopolymer Model

TL;DR

This paper models membrane protein conformations using a homopolymer approach, revealing how membrane permeability influences the nature of alpha-helix integration and phase transitions.

Contribution

It introduces a homopolymer-based model to analyze membrane protein phase behavior and elucidates the effects of membrane permeability and adsorption on transition order.

Findings

Integration becomes a second order transition at high permeability.

First order integration occurs in nonadsorbing membranes.

Transition temperature coincides with adsorption transition in certain conditions.

Abstract

The conformation and the phase diagram of a membrane protein are investigated via grand canonical ensemble approach using a homopolymer model. We discuss the nature and pathway of $\alpha$-helix integration into the membrane that results depending upon membrane permeability and polymer adsorptivity. For a membrane with the permeability larger than a critical value, the integration becomes the second order transition that occurs at the same temperature as that of the adsorption transition. For a nonadsorbing membrane, the integration is of the first order due to the aggregation of $\alpha$-helices.