Molecular dynamics simulations of a phospholipid-detergent mixture

A series of four molecular dynamics computer simulations totaling more than 40 ns in length have been carried out on hydrated bilayer systems to study the interaction between a diacylphospholipid, 1-palmitoyl-2-oleoyl-sn-glyc ero-3-phosphocholine (POPC), and an oligo(ethylene oxide) alkyl ether deter gent, C12E4. Simulations of pure lipid bilayers, pure detergent bilayers, a nd a mixed system in a 5:1 lipid-to-detergent ratio, show good agreement wi th experimental measurements. The simulations confirm experimental observat ions of the membrane's ability to significantly alter the conformations of the solute detergent molecules and offer an explanation of some seemingly c ontradictory experimental results. In addition to providing a molecular lev el explanation of the changes in solute structure, the present simulations demonstrate the importance of environment on solutes incorporated into memb ranes and show that molecular dynamics simulations is a tool with great pot ential for the study of membrane-polymer interactions.