Motional Coherence in Fluid Phospholipid Membranes

TL;DR

This study uses neutron backscattering and diffraction to explore slow, nanosecond-scale molecular motions and correlated dynamics in fluid phospholipid membranes, revealing a cooperative relaxation process.

Contribution

It combines high-resolution neutron scattering with molecular dynamics simulations to characterize nanosecond-scale correlated motions in lipid bilayers, a novel approach in membrane biophysics.

Findings

Identification of a cooperative structural relaxation in lipid membranes.

Evidence of correlated lipid dynamics over multiple length scales.

Demonstration of nanosecond-scale molecular motions in fluid phospholipid bilayers.

Abstract

We report a high energy-resolution neutron backscattering study, combined with in-situ diffraction, to investigate slow molecular motions on nanosecond time scales in the fluid phase of phospholipid bilayers of 1,2-dimyristoyl-sn-glycero-3-phoshatidylcholine (DMPC) and DMPC/40% cholesterol (wt/wt). A cooperative structural relaxation process was observed. From the in-plane scattering vector dependence of the relaxation rates in hydrogenated and deuterated samples, combined with results from a 0.1 microsecond long all atom molecular dynamics simulation, it is concluded that correlated dynamics in lipid membranes occurs over several lipid distances, spanning a time interval from pico- to nanoseconds.