Free-energy change of inserting halothane into different depths of a hydrated DMPC bilayer

Using the method of energy representation, we have calculated the free-energy change of inserting a halothane molecule into different depths of a hydrated dimyristoylphosphatidylcholine (DMPC) bilayer at pressures of 10 5 Pa to 4 × 10 7 Pa . Our results show that the free-energy change is more negative within the membrane than in bulk water. The halothane distribution is diffuse, and the preferred location is near the headgroup. The pressure effect is found to be minimal within the pressure range examined, which corresponds to previous biological experimental conditions.