A Simple Computer Model for Liquid Lipid Bilayers

TL;DR

This paper introduces a simple, efficient coarse-grained model for lipid bilayers that accurately reproduces the gel-liquid phase transition and offers two solvent environment models, maintaining membrane flexibility with minimal computational cost.

Contribution

The paper presents a novel, computationally efficient coarse-grained model for lipid bilayers that captures phase transitions and offers two solvent modeling approaches.

Findings

Both solvent models produce similar liquid-gel phase boundaries.

The model accurately reproduces the main phase transition of biological membranes.

The second solvent model retains membrane flexibility with minimal additional computational cost.

Abstract

We present a simple coarse-grained bead-and-spring model for lipid bilayers. The system has been developed to reproduce the main (gel-liquid) transition of biological membranes on intermediate length scales of a couple of nanometres and is very efficient from a computational point of view. For the solvent environment, two different models are proposed. The first model forces the lipids to form bilayers by confining their heads in two parallel planes. In the second model, the bilayer is stabilised by a surrounding gas of "phantom" solvent beads, which do not interact with each other. This model takes only slightly more computing time than the first one, while retaining the full membrane flexibility. We calculate the liquid-gel phase boundaries for both models and find that they are very similar.