Energetics of ion conduction through the K+ channel

Simon Bernèche and Benoît Roux ()
Additional contact information
Simon Bernèche: Weill Medical College of Cornell University
Benoît Roux: Weill Medical College of Cornell University

Nature, 2001, vol. 414, issue 6859, 73-77

Abstract: Abstract K+ channels are transmembrane proteins that are essential for the transmission of nerve impulses. The ability of these proteins to conduct K+ ions at levels near the limit of diffusion is traditionally described in terms of concerted mechanisms in which ion-channel attraction and ion–ion repulsion have compensating effects, as several ions are moving simultaneously in single file through the narrow pore1,2,3,4. The efficiency of such a mechanism, however, relies on a delicate energy balance—the strong ion-channel attraction must be perfectly counterbalanced by the electrostatic ion–ion repulsion. To elucidate the mechanism of ion conduction at the atomic level, we performed molecular dynamics free energy simulations on the basis of the X-ray structure of the KcsA K+ channel4. Here we find that ion conduction involves transitions between two main states, with two and three K+ ions occupying the selectivity filter, respectively; this process is reminiscent of the ‘knock-on’ mechanism proposed by Hodgkin and Keynes in 19551. The largest free energy barrier is on the order of 2–3 kcal mol-1, implying that the process of ion conduction is limited by diffusion. Ion–ion repulsion, although essential for rapid conduction, is shown to act only at very short distances. The calculations show also that the rapidly conducting pore is selective.

Date: 2001
References: Add references at CitEc
Citations: View citations in EconPapers (6)

Downloads: (external link)
https://www.nature.com/articles/35102067 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:414:y:2001:i:6859:d:10.1038_35102067

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/35102067

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().