DFT-based Conformational Analysis of a Phospholipid Molecule (DMPC)

TL;DR

This study uses DFT-D calculations to explore the conformational space of DMPC, identifying multiple low-energy isomers with consistent structural features that align with experimental NMR and vibrational data.

Contribution

It provides a detailed conformational analysis of DMPC using DFT-D, revealing multiple stable isomers and their structural characteristics consistent with experimental observations.

Findings

Fourteen low-energy conformers identified within 1 kcal/mol

All conformers share a common geometric profile

Calculated vibrational spectra agree with experimental data

Abstract

The conformational space of the dimyristoyl phosphatidylcholine (DMPC) molecule has been studied using Density Functional Theory (DFT), augmented with a damped empirical dispersion energy term (DFT-D). Fourteen ground-state isomers have been found with total energies within less than 1 kcal/mol. Despite differences in combinations of their torsion angles, all these conformers share a common geometric profile, which includes a balance of attractive, repulsive and constraint forces between and within specific groups of atoms. The definition of this profile fits with most of the structural characteristics deduced from measured NMR properties of DMPC solutions. The calculated vibrational spectrum of the molecule is in good agreement with experimental data obtained for DMPC bilayers. These results support the idea that DMPC molecules preserve their individual molecular structures in the various assemblies.