Lipid Bilayer Structure and Dynamics Studied with Molecular Dynamics Simulations and NMR Measurements

Abstract

We apply novel NMR experiments and molecular dynamics simulations to extract information about dynamics and structure of phosphatidylcholine lipid bilayers. We have developed a method to quantitatively measure rotational dynamics of hydrocarbon groups by using NMR relaxation measurements. The results from this method can be used to directly compare dynamics between simulations and experiments, which has not been possible previously. We apply this technique to phosphatidylcholine bilayers with and without cholesterol. In addition, we have measured order parameters for all hydrocarbon segments in phosphatidylcholine bilayer with and without cholesterol, and compared those to the simulation results [1]. The results reveal how cholesterol affects the molecular structure and dynamics of phosphatidylcholine glycerol and headgroup regions. The quality of simulation models will be critically discussed emphasizing the headgroup and glycerol regions. [1] Ferreira et al. PCCP 15, 1976 (2013)