help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Biophys. J. BioFAST: First Published February 4, 2005. doi:10.1529/biophysj.104.056184
© 2005 by the Biophysical Society.

A more recent version of this article appeared on May 1, 2005.
This Article
Right arrow Full Text (Rapid PDF)
Right arrow All Versions of this Article:
biophysj.104.056184v1
88/5/3095    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Author home page(s):
Gregory A. Voth
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Tepper, H. L.
Right arrow Articles by Voth, G. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Tepper, H. L.
Right arrow Articles by Voth, G. A.

BIOPHYSICAL THEORY AND MODELING

Protons May Leak Through Pure Lipid Bilayers via a Concerted Mechanism

Harald L. Tepper 1 and Gregory A. Voth 2*

1 FOM Institute for Atomic and Molecular Physics
2 University of Utah

* To whom correspondence should be addressed. E-mail: voth{at}chem.utah.edu.

Submitted on November 12, 2004
Revised on January 5, 2005
Accepted on 27 January 2005


  Abstract
Protons are known to permeate pure lipid bilayers at a rate that is anomalous compared to other small monovalent cations. The prevailing mechanism via which they cross the membrane is still unclear, and it is unknown how to probe the mechanism directly by experiment. One of the more popular theories assumes the formation of membrane-spanning single-file water wires providing a matrix along which the protons can ``hop'' over the barrier. However, free energy calculations on such structures (without the presence of an excess proton) suggest that this mechanism alone cannot account for the observed permeation rates. We use the Multi-State Empirical Valence Bond (MS-EVB) method to directly study water structures surrounding a (delocalized) excess proton on its way through the membrane. We find that membrane-spanning networks are formed around the proton rather than single-file chains. We also find that such structures are considerably stabilized in the presence of the proton, with lifetimes of several hundreds of picoseconds. The observed structures are suggestive of a new, concerted, mechanism and provide some directions for further investigations.

Key Words: Grotthuss mechanism, lipid bilayers, molecular dynamics, permeation, proton leakage, proton transport




This article has been cited by other articles:


Home page
 Proc. Natl. Acad. Sci. USAHome page
S. Schulmeister, M. Ruttorf, S. Thiem, D. Kentner, D. Lebiedz, and V. Sourjik
Protein exchange dynamics at chemoreceptor clusters in Escherichia coli
PNAS, April 29, 2008; 105(17): 6403 - 6408.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
H. Leontiadou, A. E. Mark, and S.-J. Marrink
Ion Transport across Transmembrane Pores
Biophys. J., June 15, 2007; 92(12): 4209 - 4215.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
H. Chen, B. Ilan, Y. Wu, F. Zhu, K. Schulten, and G. A. Voth
Charge Delocalization in Proton Channels, I: The Aquaporin Channels and Proton Blockage
Biophys. J., January 1, 2007; 92(1): 46 - 60.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Copyright © 2005 by the Biophysical Society.