(749c) Diffusion and Elasticity Studies of Lipid Membranes Using Molecular Dynamics Simulations

Lipid bilayers are one of the major structural elements of biological membranes which play a key role as a protective barrier and substrate for other species such as proteins to function. We have carried out molecular dynamics simulations to study the transport of a range of gases in dipalmitoylphosphatidylcholine (DPPC) bilayers with and without protein channels (e.g. OmpA). A coarse-grained model was used to provide direct insight into collective phenomena in biological membranes at large time and length scales. In our simulations, we have investigated the relationship between the elastic and dynamic properties of lipid bilayers (including those with protein channels) which are of considerable fundamental interest. These studies will enable us to understand how the local variations in the physical properties of membranes may cause membrane deformation and facilitate vesicle budding and fusion, which play a crucial role in intracellular transport. In addition we have looked at pressure-induced structural changes that are known to affect membrane behavior since structural measurements (experimental) of membranes at high pressure have been generally lacking. Finally, we have also looked at the formation of small cavities, capable of accommodating water in the protein interior, which are associated with the elastic deformation. The information obtained from our investigations will lead to a better understanding of lipid-protein systems and advance the development of biochips and drug delivery systems.