ArticleThe Journal of general physiology2005
Functional role and affinity of inorganic cations in stabilizing the tetrameric structure of the KcsA K+ channel.
Article in The Journal of general physiology, 2005. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 23 papers.
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Who cites it
23 citing papers in PubMed, 42 citations in OpenAlex.
- From Selective Permeation to Physiology in Potassium Channels.Function (Oxford, England) · 2025Review
- Conformational Dynamic Studies of Prokaryotic Potassium Channels Explored by Homo-FRET Methodologies.Methods in molecular biology (Clifton, N.J.) · 2024Article
- Molecular Events behind the Selectivity and Inactivation Properties of Model NaK-Derived Ion Channels.International journal of molecular sciences · 2022Article
- Conductance stability and Na+ interaction with Shab K+ channels under low K+ conditions.Channels (Austin, Tex.) · 2021Article
- A channel profile report of the unusual KThe Journal of general physiology · 2019Article
- Potassium channel selectivity filter dynamics revealed by single-molecule FRET.Nature chemical biology · 2019Article
- Modular Design of the Selectivity Filter Pore Loop in a Novel Family of Prokaryotic 'Inward Rectifier' (NirBac) channels.Scientific reports · 2015Article
- Structure of potassium channels.Cellular and molecular life sciences : CMLS · 2015Review
- Ubiquitination-dependent quality control of hERG K+ channel with acquired and inherited conformational defect at the plasma membrane.Molecular biology of the cell · 2013Article
- Role of methyl-induced polarization in ion binding.Proceedings of the National Academy of Sciences of the United States of America · 2013Article
- Intersubunit ionic interactions stabilize the nucleoside diphosphate kinase of Mycobacterium tuberculosis.PloS one · 2013Article
- Preferential binding of K+ ions in the selectivity filter at equilibrium explains high selectivity of K+ channels.The Journal of general physiology · 2012Article
- Mechanism for selectivity-inactivation coupling in KcsA potassium channels.Proceedings of the National Academy of Sciences of the United States of America · 2011Article
- Inactivation of the KcsA potassium channel explored with heterotetramers.The Journal of general physiology · 2010Article
- Direct regulation of prokaryotic Kir channel by cholesterol.The Journal of biological chemistry · 2009Article
- Article
- Thermal and chemical unfolding and refolding of a eukaryotic sodium channel.Biochimica et biophysica acta · 2009Article
- Intracellular potassium stabilizes human ether-à-go-go-related gene channels for export from endoplasmic reticulum.Molecular pharmacology · 2009Article
- Differential roles of blocking ions in KirBac1.1 tetramer stability.The Journal of biological chemistry · 2009Article
- Rationalizing alpha-helical membrane protein crystallization.Protein science : a publication of the Protein Society · 2008Article
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5 authors at 1 institution in 1 country.
Funding
Abstract
Crystal structures of the tetrameric KcsA K+ channel reveal seven distinct binding sites for K+ ions within the central pore formed at the fourfold rotational symmetry axis. Coordination of an individual K+ ion by eight protein oxygen atoms within the selectivity filter suggests that ion-subunit bridging by cation-oxygen interactions contributes to structural stability of the tetramer. To test this hypothesis, we examined the effect of inorganic cations on the temperature dependence of the KcsA tetramer as monitored by SDS-PAGE. Inorganic cations known to permeate or strongly block K+ channels (K+, Rb+, Cs+, Tl+, NH4+, Ba2+, and Sr2+) confer tetramer stability at higher temperatures (T0.5 range = 87 degrees C to >99 degrees C) than impermeant cations and weak blockers (Li+, Na+, Tris+, choline+; T0.5 range = 59 degrees C to 77 degrees C). Titration of K+, Ba2+, and other stabilizing cations protects against rapid loss of KcsA tetramer observed in 100 mM choline Cl at 90 degrees C. Tetramer protection titrations of K+, Rb+, Cs+, Tl+, and NH4+ at 85 degrees C or 90 degrees C exhibit apparent Hill coefficients (N) ranging from 1.7 to 3.3 and affinity constants (K0.5) ranging from 1.1 to 9.6 mM. Ba2+ and Sr2+ titrations exhibit apparent one-site behavior (N congruent with 1) with K0.5 values of 210 nM and 11 microM, respectively. At 95 degrees C in the presence of 5 mM K+, titration of Li+ or Na+ destabilizes the tetramer with K0.5 values of 57 mM and 109 mM, respectively. We conclude that specific binding interactions of inorganic cations with the selectivity filter are an important determinant of tetramer stability of KscA.
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