Free-Energy Analysis of the Preferred Configuration of Transmembrane Protein in Model Membrane: Roles of Lipid and Water

摘要

Two contrast configurations are examined for a transmembrane protein in a model membrane system. In the first one, the protein stays in the direction normal to the membrane surface, and in the second, it is buried in the membrane core. We investigate the relative stabilities of the two configurations with the free-energy analysis using the energy-representation method. The free-energy change of the protein binding is found to be more favorable for the vertical configuration. The free-energy decomposition into the contributions from lipid and water shows that the water effect overturns the lipid one to stabilize the vertical configuration.