Lateral-Pressure Profiles in Cholesterol-DPPC Bilayers

TL;DR

This study uses molecular dynamics simulations to analyze how cholesterol alters the lateral-pressure profiles in DPPC bilayers, revealing significant changes at cholesterol concentrations above 20% that could impact membrane protein interactions.

Contribution

It provides detailed insights into the cholesterol-induced modifications of lateral-pressure profiles in lipid bilayers, a novel analysis of component-specific pressure contributions.

Findings

Pressure profile becomes oscillatory above 20% cholesterol

Cholesterol alters lateral-pressure distribution significantly

Potential implications for membrane protein interactions

Abstract

By means of atomistic molecular dynamics simulations, we study cholesterol-DPPC (dipalmitoyl phosphatidylcholine) bilayers of different composition, from pure DPPC bilayers to a 1:1 mixture of DPPC and cholesterol. The lateral-pressure profiles through the bilayers are computed and separated into contributions from the different components. We find that the pressure inside the bilayer changes qualitatively for cholesterol concentrations of about 20% or higher. The pressure profile then turns from a rather flat shape into an alternating sequence of regions with large positive and negative lateral pressure. The changes in the lateral-pressure profile are so characteristic that specific interaction between cholesterol and molecules such as membrane proteins mediated solely via the lateral-pressure profile might become possible.