Sodium and potassium competition in potassium-selective and non-selective channels

David B. Sauer, Weizhong Zeng, John Canty, Yeeling Lam and Youxing Jiang ()
Additional contact information
David B. Sauer: University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9040, USA
Weizhong Zeng: University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9040, USA
John Canty: University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9040, USA
Yeeling Lam: University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9040, USA
Youxing Jiang: University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9040, USA

Nature Communications, 2013, vol. 4, issue 1, 1-9

Abstract: Abstract Potassium channels selectively conduct K+, primarily to the exclusion of Na+, despite the fact that both ions can bind within the selectivity filter. Here we perform crystallographic titration and single-channel electrophysiology to examine the competition of Na+ and K+ binding within the filter of two NaK channel mutants; one is the potassium-selective NaK2K mutant and the other is the non-selective NaK2CNG, a CNG channel pore mimic. With high-resolution structures of these engineered NaK channel constructs, we explicitly describe the changes in K+ occupancy within the filter upon Na+ competition by anomalous diffraction. Our results demonstrate that the non-selective NaK2CNG still retains a K+-selective site at equilibrium, whereas the NaK2K channel filter maintains two high-affinity K+ sites. A double-barrier mechanism is proposed to explain K+ channel selectivity at low K+ concentrations.

Date: 2013
References: Add references at CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/ncomms3721 Abstract (text/html)

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:natcom:v:4:y:2013:i:1:d:10.1038_ncomms3721

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

DOI: 10.1038/ncomms3721

Access Statistics for this article

Nature Communications is currently edited by Nathalie Le Bot, Enda Bergin and Fiona Gillespie

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