This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Serowy, S. Articles by Pohl, P. Search for Related Content PubMed PubMed Citation Articles by Serowy, S. Articles by Pohl, P.

Structural Proton Diffusion along Lipid Bilayers

Steffen Serowy^*, Sapar M. Saparov^*, Yuri N. Antonenko, Wladas Kozlovsky, Volker Hagen^* and Peter Pohl^*

^* Forschungsinstitut fuer Molekulare Pharmakologie, Campus Berlin-Buch, Robert-Rössle-Strasse 10, D-13125 Berlin, Germany; and A.N.Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119 899, Russia

Correspondence: Address reprint requests to Peter Pohl, Tel.: +49-03-94793283, Fax: +49-03-94793291, E-mail: pohl{at}fmp-berlin.de.

For H⁺ transport between protein pumps, lateral diffusion along membrane surfaces represents the most efficient pathway. Along lipid bilayers, we measured a diffusion coefficient of 5.8 x 10^-5 cm² s^-1. It is too large to be accounted for by vehicle diffusion, considering proton transport by acid carriers. Such a speed of migration is accomplished only by the Grotthuss mechanism involving the chemical exchange of hydrogen nuclei between hydrogen-bonded water molecules on the membrane surface, and the subsequent reorganization of the hydrogen-bonded network. Reconstitution of H⁺-binding sites on the membrane surface decreased the velocity of H⁺ diffusion. In the absence of immobile buffers, structural (Grotthuss) diffusion occurred over a distance of 100 µm as shown by microelectrode aided measurements of the spatial proton distribution in the immediate membrane vicinity and spatially resolved fluorescence measurements of interfacial pH. The efficiency of the anomalously fast lateral diffusion decreased gradually with an increase in mobile buffer concentration suggesting that structural diffusion is physiologically important for distances of 10 nm.

This article has been cited by other articles:

				F. M. Lasorsa, P. Pinton, L. Palmieri, P. Scarcia, H. Rottensteiner, R. Rizzuto, and F. Palmieri Peroxisomes as Novel Players in Cell Calcium Homeostasis J. Biol. Chem., May 30, 2008; 283(22): 15300 - 15308. [Abstract] [Full Text] [PDF]

				E. Barany-Wallje, S. Keller, S. Serowy, S. Geibel, P. Pohl, M. Bienert, and M. Dathe A Critical Reassessment of Penetratin Translocation Across Lipid Membranes Biophys. J., October 1, 2005; 89(4): 2513 - 2521. [Abstract] [Full Text] [PDF]

				A. Aksimentiev and K. Schulten Imaging {alpha}-Hemolysin with Molecular Dynamics: Ionic Conductance, Osmotic Permeability, and the Electrostatic Potential Map Biophys. J., June 1, 2005; 88(6): 3745 - 3761. [Abstract] [Full Text] [PDF]

				B. A. Feniouk, M. A. Kozlova, D. A. Knorre, D. A. Cherepanov, A. Y. Mulkidjanian, and W. Junge The Proton-Driven Rotor of ATP Synthase: Ohmic Conductance (10 fS), and Absence of Voltage Gating Biophys. J., June 1, 2004; 86(6): 4094 - 4109. [Abstract] [Full Text] [PDF]

				D. A. Cherepanov, W. Junge, and A. Y. Mulkidjanian Proton Transfer Dynamics at the Membrane/Water Interface: Dependence on the Fixed and Mobile pH Buffers, on the Size and Form of Membrane Particles, and on the Interfacial Potential Barrier Biophys. J., February 1, 2004; 86(2): 665 - 680. [Abstract] [Full Text] [PDF]