Coarse-Grained Molecular Dynamics Simulations of Transmembrane Assisted Permeation of Gases and Water Across Lipid Membranes

Molecular transport through biological membranes occurs in a range of important chemical and biological processes. We have carried out molecular dynamics simulations to study the transport of a range of gases in a dipalmitoylphosphatidylcholine (DPPC) bilayer membrane. By reducing the degrees of freedom and employing suitable potentials, a coarse-grained model was used to provide direct insight into collective phenomena in biological membranes at large time and length scales.

We also compare the molecular transport across lipid membrane with and without the assistance of transmembrane channels. For assisted transport we have chosen an outer membrane protein A (OmpA) -- a porin from Escherichia coli with a small pore size and high stability. MD simulations studies in such assisted transport are then also compared with available experimental data. The pore characteristics and interaction between lipid and protein were investigated and transport of water molecules within the channel was also studied. The information obtained from this study will lead to better understanding of proteins and advance the use of OmpA for development of biochips and drug delivery systems.