Effect of Lipid Layer on the Water Permeability of Aquaporin: A Molecular Dynamics Study

Aquaporin is a transmembrane protein, which facilitates selective water transport across cell membrane. High permeability of aquaporin led to many proposals to use aquaporin-embedded membranes for water purification. Recent experimental studies have shown that water permeability of aquaporin can be altered by the membrane composition. By far, there is no clear explanation how lipid composition changes the permeability of aquaporin. In this study, we simulated Aquaporin Z (AqpZ) with various conditions of lipid layers using molecular dynamics (MD) simulation. AqpZ was inserted into lipid layers having various compositions of lipids and cholesterol ratios. The osmotic permeability of aquaporin was calculated from the MD simulation and compared with experimental values. We further investigated the free energy and geometry change due to membrane composition. This study may shed light on the design optimization of aquaporin-embedded membrane.