Proceedings of the National Academy of Sciences - PNAS, 2009-09, Vol.106 (38), p.16074-16077
2009
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- Autor(en) / Beteiligte
- Titel
- Atypical mechanism of conduction in potassium channels
- Ist Teil von
- Proceedings of the National Academy of Sciences - PNAS, 2009-09, Vol.106 (38), p.16074-16077
- Ort / Verlag
- United States: National Academy of Sciences
- Erscheinungsjahr
- 2009
- Quelle
- MEDLINE
- Beschreibungen/Notizen
- Potassium channels can conduct passively K⁺ ions with rates of up to [almost equal to]10⁸ ions per second at physiological conditions, and they are selective to these species by a factor of 10⁴ over Na⁺ ions. Ion conduction has been proposed to involve transitions between 2 main states, with 2 or 3 K⁺ ions occupying the selectivity filter separated by an intervening water molecule. The largest free energy barrier of such a process was reported to be of the order of 2-3 kcal mol⁻¹. Here, we present an alternative mechanism for conduction of K⁺ in potassium channels where site vacancies are involved, and we propose that coexistence of several ion permeation mechanisms is energetically possible. Conduction can be described as a more anarchic phenomenon than previously characterized by the concerted translocations of K⁺-water-K⁺.
- Sprache
- Englisch
- Identifikatoren
- ISSN: 0027-8424eISSN: 1091-6490DOI: 10.1073/pnas.0903226106Titel-ID: cdi_jstor_primary_40485022
- Format
- –
- Schlagworte
- Amino acids, Atoms, Bacterial Proteins - chemistry, Bacterial Proteins - physiology, Binding Sites, Biochemistry, Biological Sciences, Computer Simulation, Conduction, Crystallography, X-Ray, Free energy, Ion Channel Gating, Ions, Models, Molecular, Molecular dynamics, Molecules, Physical Sciences, Potassium, Potassium - chemistry, Potassium channels, Potassium Channels - chemistry, Potassium Channels - physiology, Protein Conformation, Protein Structure, Tertiary, Sodium, Thermodynamics, Water, Water - chemistry