ArticleThe Journal of general physiology2006
Detection of the opening of the bundle crossing in KcsA with fluorescence lifetime spectroscopy reveals the existence of two gates for ion conduction.
Article in The Journal of general physiology, 2006. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 61 papers.
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Who cites it
61 citing papers in PubMed.
- Similarity of the ion occupations of KChannels (Austin, Tex.) · 2026Article
- A Historical Outline of Fluorescence Spectroscopy in Ion Channel Research.Advances in experimental medicine and biology · 2026Review
- Conformational Dynamic Studies of Prokaryotic Potassium Channels Explored by Homo-FRET Methodologies.Methods in molecular biology (Clifton, N.J.) · 2024Article
- Full opening of helix bundle crossing does not lead to NaK channel activation.The Journal of general physiology · 2022Article
- The nonconducting W434F mutant adopts upon membrane depolarization an inactivated-like state that differs from wild-type Shaker-IR potassium channels.Science advances · 2022Article
- Probing the Structural Dynamics of the Activation Gate of KcsA Using Homo-FRET Measurements.International journal of molecular sciences · 2021Article
- The Selectivity Filter Is Involved in the U-Type Inactivation Process of Kv2.1 and Kv3.1 Channels.Biophysical journal · 2020Article
- Gating modules of the AMPA receptor pore domain revealed by unnatural amino acid mutagenesis.Proceedings of the National Academy of Sciences of the United States of America · 2019Article
- Conformational plasticity in the KcsA potassium channel pore helix revealed by homo-FRET studies.Scientific reports · 2019Article
- Site-Directed Fluorescence Approaches for Dynamic Structural Biology of Membrane Peptides and Proteins.Frontiers in molecular biosciences · 2019Review
- Rapid constriction of the selectivity filter underlies C-type inactivation in the KcsA potassium channel.The Journal of general physiology · 2018Article
- Extended beta distributions open the access to fast gating in bilayer experiments-assigning the voltage-dependent gating to the selectivity filter.FEBS letters · 2017Article
- Hysteresis of KcsA potassium channel's activation- deactivation gating is caused by structural changes at the channel's selectivity filter.Proceedings of the National Academy of Sciences of the United States of America · 2017Article
- Closed-state inactivation involving an internal gate in Kv4.1 channels modulates pore blockade by intracellular quaternary ammonium ions.Scientific reports · 2016Article
- Discovery and characterisation of a novel toxin from Dendroaspis angusticeps, named Tx7335, that activates the potassium channel KcsA.Scientific reports · 2016Article
- Competing Lipid-Protein and Protein-Protein Interactions Determine Clustering and Gating Patterns in the Potassium Channel from Streptomyces lividans (KcsA).The Journal of biological chemistry · 2015Article
- Channel function reconstitution and re-animation: a single-channel strategy in the postcrystal age.The Journal of physiology · 2015Review
- The Hydrophobic Effect Contributes to the Closed State of a Simplified Ion Channel through a Conserved Hydrophobic Patch at the Pore-Helix Crossing.Frontiers in pharmacology · 2015Article
- Mechanisms of activation of voltage-gated potassium channels.Acta naturae · 2014Article
- Regulation of ion channel function by the host lipid bilayer examined by a stopped-flow spectrofluorometric assay.Biophysical journal · 2014Article
1 more citing papers are in PubMed but not listed here.
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5 authors.
Funding
Abstract
The closed KcsA channel structure revealed a crossing of the cytosolic ends of the transmembrane helices blocking the permeation pathway. It is generally agreed that during channel opening this helical bundle crossing has to widen in order to enable access to the inner cavity. Here, we address the question of whether the opening of the inner gate is sufficient for ion conduction, or if a second gate, located elsewhere, may interrupt the ion flow. We used fluorescence lifetime measurements on KcsA channels labeled with tetramethylrhodamine at residues in the C-terminal end of TM2 to report on the opening of the lower pore region. We found two populations of channels with different fluorescence lifetimes, whose relative distribution agrees with the open probability of the channel. The absolute fraction of channels found with an open bundle crossing is too high to explain the low open probability of the KcsA-WT channel. We found the same distribution as in the WT channel between open and closed bundle crossing for two KcsA mutants, A73E and E71A, which significantly increase open probability at low pH. These two results strongly suggest that a second gate in the ion permeation pathway exists. The location of the mutations A73E and E71A suggests that the second gate may be the selectivity filter, which resides in an inactivated state under steady-state conditions. Since the long closed times observed in KcsA-WT are not present in KcsA-A73E or -E71A, we propose that KcsA-WT remains predominantly in a state with an open bundle crossing but closed (inactivated) second gate, while the mutations A73E and E71A sharply decrease the tendency to enter in the inactivated state, and as a consequence, the second gate is predominantly open at steady state. The ability to monitor the opening of the bundle crossing optically enables the direct recording of the movement of the pore helices while the channel is functioning.
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