The conduction pathway of potassium channels is water free under physiological conditions.

Autor:	Öster C; Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany., Hendriks K; Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany., Kopec W; Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany., Chevelkov V; Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany., Shi C; Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany., Michl D; Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany., Lange S; Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany., Sun H; Section Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany., de Groot BL; Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany., Lange A; Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany.; Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.
Jazyk:	angličtina
Zdroj:	Science advances [Sci Adv] 2019 Jul 31; Vol. 5 (7), pp. eaaw6756. Date of Electronic Publication: 2019 Jul 31 (Print Publication: 2019).
DOI:	10.1126/sciadv.aaw6756
Abstrakt:	Ion conduction through potassium channels is a fundamental process of life. On the basis of crystallographic data, it was originally proposed that potassium ions and water molecules are transported through the selectivity filter in an alternating arrangement, suggesting a "water-mediated" knock-on mechanism. Later on, this view was challenged by results from molecular dynamics simulations that revealed a "direct" knock-on mechanism where ions are in direct contact. Using solid-state nuclear magnetic resonance techniques tailored to characterize the interaction between water molecules and the ion channel, we show here that the selectivity filter of a potassium channel is free of water under physiological conditions. Our results are fully consistent with the direct knock-on mechanism of ion conduction but contradict the previously proposed water-mediated knock-on mechanism.
Databáze:	MEDLINE
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