Structure of POPC Lipid Bilayers in OPLS3e Force Field
Milla Kurki1, Antti Poso1, Piia Bartos1
1School of Pharmacy, University of Eastern Finland, Kuopio Campus, Yliopistonranta 1 C, P.O. Box 1627, 70211 Kuopio, Finland.
Journal of Chemical Information and Modeling
|August 31, 2022
Summary
The OPLS3e force field accurately models POPC lipid bilayers for molecular dynamics simulations. However, it overestimates cation binding, particularly Ca2+, in high-ion environments.
Area of Science:
- Biomolecular simulations
- Computational biophysics
- Membrane biophysics
Background:
- Accurate force fields are essential for molecular dynamics (MD) simulations of biomembranes.
- The OPLS3e force field's performance for lipid bilayers requires thorough evaluation.
Purpose of the Study:
- To assess the OPLS3e force field's accuracy in simulating 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) lipid bilayers.
- To investigate the impact of hydration and ion concentration on OPLS3e's performance.
Main Methods:
- Molecular dynamics simulations of POPC lipid bilayers.
- Analysis of carbon-hydrogen order parameters (SCH) across different lipid regions.
- Comparison with experimental data and other force fields (CHARMM36).
Main Results:
- OPLS3e accurately reproduces experimental SCH values for POPC lipid headgroups, glycerol backbone, and acyl tails.
- OPLS3e's behavior is comparable to the CHARMM36 force field under various conditions.
- OPLS3e significantly overestimates cation binding, especially Ca2+, in high-ion concentrations.
Conclusions:
- OPLS3e is suitable for simulating POPC bilayers in many biologically relevant scenarios.
- The overestimation of cation binding by OPLS3e can alter membrane surface charge and ion concentrations, posing challenges for specific applications.
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