Mechanical properties of lipid bilayers from molecular dynamics simulation

Area of Science:

• Biophysics
• Computational Chemistry
• Materials Science

Background:

• Lipid bilayers are fundamental to cell membranes.
• Accurate simulation of lipid properties is crucial for understanding membrane behavior.
• Existing computational models require validation against experimental data.

Purpose of the Study:

• To validate the CHARMM36 force field for lipid bilayer simulations.
• To computationally determine key lipid bilayer mechanical properties.
• To compare simulated properties with experimental measurements.

Main Methods:

• Molecular dynamics simulations using the CHARMM36 force field.
• Analysis of 12 representative homogenous lipid bilayers.
• Calculation of lipid areas (Aℓ), area compressibilities (KA), bending constants (KC), and spontaneous curvatures (c0).

Main Results:

• Simulated lipid areas (Aℓ) and area compressibilities (KA) show excellent agreement with experimental data.
• Bilayer bending constants (KC) from simulations closely match vesicle flicker experiments.
• Simulated spontaneous curvatures (c0) are approximately 30% lower than experimental values for monolayers.

Conclusions:

• The CHARMM36 force field provides reliable predictions for lipid bilayer area and compressibility.
• Simulations offer a powerful tool for studying lipid bilayer mechanics, particularly bending constants.
• Discrepancies in spontaneous curvature highlight areas for refinement in both simulation and experimental interpretation.