(650a) Lipid Diversity: Is It Important in Modeling Organism and Organelle Membranes?

Biological membranes form a barrier to protect the cell from its environment and selectively control the entrance/exit of small molecules.  These membranes consist of lipids, such as phospholipids and sterols, and proteins that act as gates to control molecule transport across the amphiphillic surface.  Results from both experimental and simulation methods are often required to elucidate structural, mechanical, and dynamical properties of membranes at the molecular level.  The importance of lipid composition and lipid types will be presented with focus on model singled-celled organisms (bacteria and yeast).  Methods for developing accurate force field parameters from quantum mechanics will be briefly discussed.  For bacterial membranes, chain branching and replacement of carbon-carbon double bonds with a cyclopropane-moiety influence structural membrane properties.  In addition to lipid diversity on membrane properties, the influence of membrane composition on membrane-protein interaction will also be presented.  Although the focus has been on developing model membranes for computational purposes, our results also have implications to experimental in vitro studies.