The mobility of single-file water molecules is governed by the number of H-bonds they may form with channel-lining residues.

ABSTRACT: Channel geometry governs the unitary osmotic water channel permeability, p_f, according to classical hydrodynamics. Yet, p_f varies by several orders of magnitude for membrane channels with a constriction zone that is one water molecule in width and four to eight molecules in length. We show that both the p_f of those channels and the diffusion coefficient of the single-file waters within them are determined by the number N_H of residues in the channel wall that may form a hydrogen bond with the single-file waters. The logarithmic dependence of water diffusivity on N_H is in line with the multiplicity of binding options at higher N_H densities. We obtained high-precision p_f

SUBMITTER: Horner A 

PROVIDER: S-EPMC4496530 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature