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Single file water transport through nanopores (FWF)

Project Leader: Univ.-Prof. Dr. Peter Pohl

FWF Project P23679

1 September 2011 - 31 January 2016

Confinement of water by pore geometry to a one-dimensional file of molecules alters its physico-chemical properties. These changes are believed to be responsible for the discrepancies in water mobilities (i) predicted from continuum or kinetic models, (ii) determined by molecular dynamics simulations and (iii) derived from the experiment. Accordingly, (i) friction is thought to linearly reduce mobility with channel length or (ii) salvation is believed to form the main energetic barrier so that mobility is independent on channel length or (iii) multiple water binding sites in the pore are postulated to explain the observed exponential decrease of mobility with pore length. Goal of the current proposal is to reveal the true molecular mechanism of single file transport. It addresses the following questions: (i) What determines the energetics of water entry into the pore? Do lipid charged headgroups or amino acids at the channel mouth have a significant effect on water dehydration? Does the presence of polar lipid headgroups or carbonyl groups play a role? (ii) What determines the height of the internal barriers? Is it possible to tune these barriers by introducing hydrophobic elements into the pore wall? (iii) How important is the strength of the hydrogen bonding between the permeating water molecules, i.e. is there an isotope effect in single file water transport? To answer these questions osmotic water transport through reconstituted nanopores is measured by electrochemical microscopy. To derive the single nanopore permeability, the number of pores is counted by current measurements under voltage clamp conditions. The results are expected to contribute to the understanding of hydrophobic gating of receptors, single file transport through ion channels, and the development of nanofluidics devices.

Publications

Water Determines the Structure and Dynamics of Proteins
Marie-Claire Bellissent-Funel, Ali Hassanali, Martina Havenith, Richard Henchman, Peter Pohl, Fabio Sterpone, David van der Spoel, Yao Xu, and Angel E Garcia¶
Chem. Rev., 17 May 2016.

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The mobility of single-file water molecules is governed by the number of H-bonds they may form with channel-lining residues
Andreas Horner, Florian Zocher, Johannes Preiner, Nicole Ollinger, Chistine Siligan, Sergey A. Akimov and Peter Pohl
Sci. Adv. 1, e1400083 (2015).

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Design of Peptide-Membrane Interactions to Modulate Single-File Water Transport through Modified Gramicidin Channels.
Guillem Portella, Tanja Polupanow, Florian Zocher, Danila A. Boytsov, Peter Pohl, Ulf Diederichsen, Bert L. de Groot
Biophysical Journal, Volume 103, Issue 8, pp. 1698-705. Published: 17 October 2012.

Abstract  (Neues Fenster)

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