Bending modulus of lipid membranes from density correlation functions.
File(s)
Published version
Author(s)
Hernández-Muñoz, Jose
Bresme, Fernando
Tarazona, Pedro
Chacón, Enrique
Type
Journal Article
Abstract
The bending modulus κ quantifies the elasticity of biological membranes in terms of the free energy cost of increasing the membrane corrugation. Molecular dynamics (MD) simulations provide a powerful approach to quantify κ by analyzing the thermal fluctuations of the lipid bilayer. However, existing methods require the identification and filtering of non-mesoscopic fluctuation modes. State of the art methods rely on identifying a smooth surface to describe the membrane shape. These methods introduce uncertainties in calculating κ since they rely on different criteria to select the relevant fluctuation modes. Here, we present a method to compute κ using molecular simulations. Our approach circumvents the need to define a mesoscopic surface or an orientation field for the lipid tails explicitly. The bending and tilt moduli can be extracted from the analysis of the density correlation function (DCF). The method introduced here builds on the Bedeaux and Weeks (BW) theory for the DCF of fluctuating interfaces and on the coupled undulatory (CU) mode introduced by us in previous work. We test the BW-DCF method by computing the elastic properties of lipid membranes with different system sizes (from 500 to 6000 lipid molecules) and using coarse-grained (for POPC and DPPC lipids) and fully atomistic models (for DPPC). Further, we quantify the impact of cholesterol on the bending modulus of DPPC bilayers. We compare our results with bending moduli obtained with X-ray diffraction data and different computer simulation methods.
Date Issued
2022-05-10
Date Acceptance
2022-04-01
Citation
Journal of Chemical Theory and Computation, 2022, 18 (5), pp.3151-3163
ISSN
1549-9618
Publisher
American Chemical Society
Start Page
3151
End Page
3163
Journal / Book Title
Journal of Chemical Theory and Computation
Volume
18
Issue
5
Copyright Statement
© 2022 The Authors. Published by American Chemical Society. This work is published under CC BY 4.0 International licence.
License URL
Sponsor
The Leverhulme Trust
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/35389648
Grant Number
RPG-2018-384
Subjects
Cell Membrane
Cholesterol
Lipid Bilayers
Molecular Dynamics Simulation
X-Ray Diffraction
Cell Membrane
Cholesterol
Lipid Bilayers
X-Ray Diffraction
Molecular Dynamics Simulation
Chemical Physics
0307 Theoretical and Computational Chemistry
0601 Biochemistry and Cell Biology
0803 Computer Software
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2022-04-07