Computer Simulations of a Heterogeneous Membrane with Enhanced Sampling Techniques

TL;DR

This paper evaluates enhanced sampling techniques combined with coarse-grained membrane models to significantly accelerate the simulation of heterogeneous membranes, aiding the study of phase separation and domain formation.

Contribution

It introduces a combined approach of MDAS and MC-MD with Martini coarse-grained models to improve simulation efficiency of membrane phase behavior.

Findings

Achieved 3 to 10 times faster equilibration compared to standard MD.

Demonstrated effectiveness in studying membrane phase separation.

Provided a practical tool for biological membrane research.

Abstract

Computational determination of the equilibrium state of heterogeneous phospholipid mem-branes is a significant challenge. We wish to explore the rich phase diagram of these multi-component systems. However, the diffusion and mixing times in membranes are long com-pared to typical times of computer simulations. To speed up the relaxation times, advanced simulation methods are used. We evaluate the combination of enhanced sampling tech-niques such as MDAS (Molecular Dynamics with Alchemical Steps) and MC-MD (Monte Carlo with Molecular Dynamics) with a coarse-grained model of membranes (Martini) to re-duce the number of steps and force evaluations that are needed to reach equilibrium. We illustrate a significant gain compared to straightforward Molecular Dynamics of the Martini model by factors between three to ten. The combination is a useful tool to enhance the study of phase separation and the formation of domains in biological membranes.