ArticleThe Journal of biological chemistry2009
Differential roles of blocking ions in KirBac1.1 tetramer stability.
Article in The Journal of biological chemistry, 2009. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 26 papers.
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Who cites it
26 citing papers in PubMed, 29 citations in OpenAlex.
- Atomistic Mechanism of Calcium-Mediated Inward Rectification of the MthK Potassium Channel by Solid-State NMR and MD Simulations.Journal of the American Chemical Society · 2025Article
- From Selective Permeation to Physiology in Potassium Channels.Function (Oxford, England) · 2025Review
- Coordination of bilayer properties by an inward-rectifier KJournal of structural biology: X · 2024Article
- Cooperative Gating of a KJournal of the American Chemical Society · 2024Article
- pH-induced conformational changes in the selectivity filter of a potassium channel lead to alterations in its selectivity and permeation properties.Frontiers in pharmacology · 2024Article
- Article
- Pore-forming transmembrane domains control ion selectivity and selectivity filter conformation in the KirBac1.1 potassium channel.The Journal of general physiology · 2021Article
- Water Accessibility Refinement of the Extended Structure of KirBac1.1 in the Closed State.Frontiers in molecular biosciences · 2021Article
- The Lipid Activation Mechanism of a Transmembrane Potassium Channel.Journal of the American Chemical Society · 2020Article
- Conformational changes upon gating of KirBac1.1 into an open-activated state revealed by solid-state NMR and functional assays.Proceedings of the National Academy of Sciences of the United States of America · 2020Article
- Potassium channel selectivity filter dynamics revealed by single-molecule FRET.Nature chemical biology · 2019Article
- Studying Structural Dynamics of Potassium Channels by Single-Molecule FRET.Methods in molecular biology (Clifton, N.J.) · 2018Article
- Conformational changes at cytoplasmic intersubunit interactions control Kir channel gating.The Journal of biological chemistry · 2017Article
- Structural dynamics of potassium-channel gating revealed by single-molecule FRET.Nature structural & molecular biology · 2016Article
- Modular Design of the Selectivity Filter Pore Loop in a Novel Family of Prokaryotic 'Inward Rectifier' (NirBac) channels.Scientific reports · 2015Article
- Molecular Dynamics Simulations of KirBac1.1 Mutants Reveal Global Gating Changes of Kir Channels.Journal of chemical information and modeling · 2015Article
- Assembly of AMPA receptors: mechanisms and regulation.The Journal of physiology · 2015Review
- Role of methyl-induced polarization in ion binding.Proceedings of the National Academy of Sciences of the United States of America · 2013Article
- Domain organization of the ATP-sensitive potassium channel complex examined by fluorescence resonance energy transfer.The Journal of biological chemistry · 2013Article
- Structural rearrangements underlying ligand-gating in Kir channels.Nature communications · 2012Article
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Authors and funding
5 authors at 2 institutions in 1 country.
Funding
Abstract
Potassium channels are tetrameric proteins that mediate K(+)-selective transmembrane diffusion. For KcsA, tetramer stability depends on interactions between permeant ions and the channel pore. We have examined the role of pore blockers on the tetramer stability of KirBac1.1. In 150 mm KCl, purified KirBac1.1 protein migrates as a monomer (approximately 40 kDa) on SDS-PAGE. Addition of Ba(2+) (K(1/2) approximately 50 microm) prior to loading results in an additional tetramer band (approximately 160 kDa). Mutation A109C, at a residue located near the expected Ba(2+)-binding site, decreased tetramer stabilization by Ba(2+) (K(1/2) approximately 300 microm), whereas I131C, located nearby, stabilized tetramers in the absence of Ba(2+). Neither mutation affected Ba(2+) block of channel activity (using (86)Rb(+) flux assay). In contrast to Ba(2+), Mg(2+) had no effect on tetramer stability (even though Mg(2+) was a potent blocker). Many studies have shown Cd(2+) block of K(+) channels as a result of cysteine substitution of cavity-lining M2 (S6) residues, with the implicit interpretation that coordination of a single ion by cysteine side chains along the central axis effectively blocks the pore. We examined blocking and tetramer-stabilizing effects of Cd(2+) on KirBac1.1 with cysteine substitutions in M2. Cd(2+) block potency followed an alpha-helical pattern consistent with the crystal structure. Significantly, Cd(2+) strongly stabilized tetramers of I138C, located in the center of the inner cavity. This stabilization was additive with the effect of Ba(2+), consistent with both ions simultaneously occupying the channel: Ba(2+) at the selectivity filter entrance and Cd(2+) coordinated by I138C side chains in the inner cavity.
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