Molecular dynamics simulation on the effect of pore hydrophobicity on water transport through aquaporin-mimic nanopores

摘要

Aquaporins, which are membrane proteins of interest due to their properties of fast water transport and water selectivity, were mimicked by hourglass-shaped nanopores with a positive charge. Upon investigation of water transport phenomenon in these nanopores, by varying the hydrophobicity of the inner surface, a maximum water flux of 29 ns(-1) was obtained at a hydrophobic state of Opore 101, and this was over thrice the lowest water flux in this study. The entrance, center, and exit regions of the pore were found to exhibit different water transport mechanisms. In the center region, the average distance between water molecules decreased constantly as pore hydrophobicity increased, while opposite results were obtained for the entrance and exit regions. The detailed structure of water molecules during transport was investigated: a single-file water structure formed in the center region, while the water molecules became bulk-state-like in the entrance and exit regions. From the density profile of the water molecules, the lowest energy barrier was found to appear in the hydrophobic state of theta(pore) = 101 degrees. (C) 2015 Elsevier B.V. All rights reserved.