A Computational Approach to Model Neutron Scattering Data from Lipid Bilayers

Abstract

Biological cell membranes are responsible for a range of structural and dynamical phenomena crucial to a cell's well-being and its associated functions. Due to the com- plexity of cell membranes, lipid bilayer systems are often used as biomimetic models. These systems have led to signicant insights into vital membrane phenomena such as domain formation, passive permeation and protein insertion. Experimental observa- tions of membrane structure and dynamics are, however, limited in resolution, both spatially and temporally. Importantly, computer simulations are starting to play a more prominent role in interpreting experimental results, enabling a molecular under- standing of lipid membranes. In particular, the synergy between scattering experiments and simulations oers opportunities for new discoveries in membrane physics, as the length and time scales probed by molecular dynamics (MD) simulations parallel those of experiments. Here, we describe a coarse-grained MD simulation approach that mim- ics neutron scattering data from large unilamellar lipid vesicles over a range of bilayer rigidity. Specically, we simulate vesicle form factors and membrane thickness fluctuations determined from small angle neutron scattering (SANS) and neutron spin echo (NSE) experiments, respectively. Our simulations accurately reproduce trends from experiments and lay the groundwork for investigations of more complex membrane systems.