Polarizable atomic multipole-based force field for DOPC and POPE membrane lipids

ABSTRACT

A polarizable atomic multipole-based force field for the membrane bilayer models 1,2-dioleoyl-phosphocholine (DOPC) and 1-palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE) has been developed. The force field adopts the same framework as the Atomic Multipole Optimized Energetics for Biomolecular Applications (AMOEBA) model, in which the charge distribution of each atom is represented by the permanent atomic monopole, dipole and quadrupole moments. Many-body polarization including the inter- and intra-molecular polarization is modelled in a consistent manner with distributed atomic polarizabilities. The van der Waals parameters were first transferred from existing AMOEBA parameters for small organic molecules and then optimised by fitting to ab initio intermolecular interaction energies between models and a water molecule. Molecular dynamics simulations of the two aqueous DOPC and POPE membrane bilayer systems, consisting of 72 model molecules, were then carried out to validate the force field parameters. Membrane width, area per lipid, volume per lipid, deuterium order parameters, electron density profile, etc. were consistent with experimental values.

KEYWORDS:

• polarizable atomic multipole-based force field
• membrane bilayers model
• DOPC
• POPE

Acknowledgments

This work was financially supported by the National Natural Science Foundation of China (21573217, 21375126, 31370714, and 91430110) and Chinese Academy of Medical Sciences Medicine and Health Science and Technology Innovation Project (2017-I2M-1-012). The authors thank Pengyu Ren and Changsheng Zhang for their fruitful discussion and encouragement for this work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

National Natural Science Foundation of China [grant number 21375126], [grant number 21573217], [grant number 31370714], [grant number 91430110]; Chinese Academy of Medical Sciences Medicine and Health Science and Technology Innovation Project [grant number 2017-I2M-1-012].