Ion permeation in K⁺ channels occurs by direct Coulomb knock-on

David A. Köpfer; Chen Song; Tim Gruene; George M. Sheldrick; Ulrich Zachariae; Bert L. de Groot

doi:10.1126/science.1254840

Ion permeation in K⁺ channels occurs by direct Coulomb knock-on

David A. Köpfer
, Chen Song (Lead / Corresponding author)
, Tim Gruene
, George M. Sheldrick
, Ulrich Zachariae (Lead / Corresponding author)
, Bert L. de Groot (Lead / Corresponding author)

SCI Physics

Research output: Contribution to journal › Article › peer-review

307 Citations (Scopus)

Abstract

Potassium channels selectively conduct K⁺ions across cellular membranes with extraordinary efficiency. Their selectivity filter exhibits four binding sites with approximately equal electron density in crystal structures with high K⁺concentrations, previously thought to reflect a superposition of alternating ion- and water-occupied states. Consequently, cotranslocation of ions with water has become a widely accepted ion conduction mechanism for potassium channels. By analyzing more than 1300 permeation events from molecular dynamics simulations at physiological voltages, we observed instead that permeation occurs via ion-ion contacts between neighboring K⁺ ions. Coulomb repulsion between adjacent ions is found to be the key to high-efficiency K⁺conduction. Crystallographic data are consistent with directly neighboring K⁺ ions in the selectivity filter, and our model offers an intuitive explanation for the high throughput rates of K⁺ channels.

Original language	English
Pages (from-to)	352-355
Number of pages	4
Journal	Science
Volume	346
Issue number	6207
DOIs	https://doi.org/10.1126/science.1254840
Publication status	Published - 17 Oct 2014

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10.1126/science.1254840

Zachariae, Ulrich
- Biological Chemistry and Drug Discovery - Professor of Molecular Biophysics
Person: Academic

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title = "Ion permeation in K⁺ channels occurs by direct Coulomb knock-on",

abstract = "Potassium channels selectively conduct K+ions across cellular membranes with extraordinary efficiency. Their selectivity filter exhibits four binding sites with approximately equal electron density in crystal structures with high K+concentrations, previously thought to reflect a superposition of alternating ion- and water-occupied states. Consequently, cotranslocation of ions with water has become a widely accepted ion conduction mechanism for potassium channels. By analyzing more than 1300 permeation events from molecular dynamics simulations at physiological voltages, we observed instead that permeation occurs via ion-ion contacts between neighboring K+ ions. Coulomb repulsion between adjacent ions is found to be the key to high-efficiency K+conduction. Crystallographic data are consistent with directly neighboring K+ ions in the selectivity filter, and our model offers an intuitive explanation for the high throughput rates of K+ channels.",

author = "K{\"o}pfer, \{David A.\} and Chen Song and Tim Gruene and Sheldrick, \{George M.\} and Ulrich Zachariae and \{de Groot\}, \{Bert L.\}",

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T1 - Ion permeation in K⁺ channels occurs by direct Coulomb knock-on

AU - Köpfer, David A.

AU - Song, Chen

AU - Gruene, Tim

AU - Sheldrick, George M.

AU - Zachariae, Ulrich

AU - de Groot, Bert L.

PY - 2014/10/17

Y1 - 2014/10/17

N2 - Potassium channels selectively conduct K+ions across cellular membranes with extraordinary efficiency. Their selectivity filter exhibits four binding sites with approximately equal electron density in crystal structures with high K+concentrations, previously thought to reflect a superposition of alternating ion- and water-occupied states. Consequently, cotranslocation of ions with water has become a widely accepted ion conduction mechanism for potassium channels. By analyzing more than 1300 permeation events from molecular dynamics simulations at physiological voltages, we observed instead that permeation occurs via ion-ion contacts between neighboring K+ ions. Coulomb repulsion between adjacent ions is found to be the key to high-efficiency K+conduction. Crystallographic data are consistent with directly neighboring K+ ions in the selectivity filter, and our model offers an intuitive explanation for the high throughput rates of K+ channels.

AB - Potassium channels selectively conduct K+ions across cellular membranes with extraordinary efficiency. Their selectivity filter exhibits four binding sites with approximately equal electron density in crystal structures with high K+concentrations, previously thought to reflect a superposition of alternating ion- and water-occupied states. Consequently, cotranslocation of ions with water has become a widely accepted ion conduction mechanism for potassium channels. By analyzing more than 1300 permeation events from molecular dynamics simulations at physiological voltages, we observed instead that permeation occurs via ion-ion contacts between neighboring K+ ions. Coulomb repulsion between adjacent ions is found to be the key to high-efficiency K+conduction. Crystallographic data are consistent with directly neighboring K+ ions in the selectivity filter, and our model offers an intuitive explanation for the high throughput rates of K+ channels.

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VL - 346

SP - 352

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JO - Science

JF - Science

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ER -

Ion permeation in K⁺ channels occurs by direct Coulomb knock-on

Abstract

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Zachariae, Ulrich

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