Toward Quantitative Coarse-Grained Models of Lipids with Fluids Density Functional Theory

Area of Science:

• Computational chemistry
• Biophysics
• Materials science

Background:

• Lipid bilayers are crucial biological structures.
• Accurate computational models are needed to study lipid bilayer properties.
• Coarse-grained models offer computational efficiency but require careful parameterization.

Purpose of the Study:

• To develop and validate optimal coarse-grained models for lipid bilayers.
• To apply these models within fluids density functional theory (fluids-DFT) calculations.
• To investigate dipalmitoylphosphatidylcholine (DPPC) lipid bilayers in water.

Main Methods:

• Utilized modified-iSAFT theory for bonded systems.
• Employed fundamental measures theory (FMT) for hard sphere reference fluids.
• Developed a novel pressure control approach for fluids-DFT calculations.

Main Results:

• Demonstrated that optimized coarse-grained models can match experimental DPPC bilayer thickness and area per lipid.
• Showed that excessive coarse-graining can compromise model accuracy.
• Found reasonable agreement between predicted and prior results for area compressibility moduli and lateral pressure profiles.

Conclusions:

• It is feasible to create accurate coarse-grained lipid bilayer models for fluids-DFT.
• Model parameterization and level of coarse-graining are critical for reproducing experimental properties.
• The developed methods facilitate advanced bilayer simulations, including partitioning and zero-tension studies.