Publication Date:
2014-10-18
Description:
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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kopfer, David A -- Song, Chen -- Gruene, Tim -- Sheldrick, George M -- Zachariae, Ulrich -- de Groot, Bert L -- New York, N.Y. -- Science. 2014 Oct 17;346(6207):352-5. doi: 10.1126/science.1254840.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, 37077 Gottingen, Germany. ; Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK. sc3210@gmail.com u.zachariae@dundee.ac.uk bgroot@gwdg.de. ; Department of Structural Chemistry, University of Gottingen, 37077 Gottingen, Germany. ; School of Engineering, Physics and Mathematics, University of Dundee, Dundee DD1 4HN, UK. College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK. sc3210@gmail.com u.zachariae@dundee.ac.uk bgroot@gwdg.de. ; Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, 37077 Gottingen, Germany. sc3210@gmail.com u.zachariae@dundee.ac.uk bgroot@gwdg.de.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25324389" target="_blank"〉PubMed〈/a〉
Keywords:
Bacterial Proteins/*chemistry/metabolism
;
Binding Sites
;
Crystallography, X-Ray
;
Molecular Dynamics Simulation
;
Potassium/*metabolism
;
Potassium Channels/*chemistry/metabolism
;
Protein Conformation
;
*Static Electricity
;
Water
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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