Binding kinetics of quaternary ammonium ions in Kcv potassium channels
Kcv channels from plant viruses represent the autonomous pore module of potassium channels, devoid of any regulatory domains. These small proteins show very reproducible single-channel behavior in planar lipid bilayers. Thus, they are an optimum system for the study of the biophysics of ion transpor...
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| Format: | Article |
| Language: | English |
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Taylor & Francis Group
2024-12-01
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| Series: | Channels |
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| Online Access: | https://www.tandfonline.com/doi/10.1080/19336950.2024.2402749 |
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| _version_ | 1846136223694848000 |
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| author | Tobias Korn Ulf-Peter Hansen Tobias Sebastian Gabriel Oliver Rauh Nils Drexler Indra Schroeder |
| author_facet | Tobias Korn Ulf-Peter Hansen Tobias Sebastian Gabriel Oliver Rauh Nils Drexler Indra Schroeder |
| author_sort | Tobias Korn |
| collection | DOAJ |
| description | Kcv channels from plant viruses represent the autonomous pore module of potassium channels, devoid of any regulatory domains. These small proteins show very reproducible single-channel behavior in planar lipid bilayers. Thus, they are an optimum system for the study of the biophysics of ion transport and gating. Structural models based on homology modeling have been used successfully, but experimental structural data are currently not available. Here we determine the size of the cytosolic pore entrance by studying the blocker kinetics. Blocker binding and dissociation rate constants ranging from 0.01 to 1000 ms−1 were determined for different quaternary ammonium ions. We found that the cytosolic pore entrance of KcvNTS must be at least 11 Å wide. The results further indicate that the residues controlling a cytosolic gate in one of the Kcv isoforms influence blocker binding/dissociation as well as a second gate even when the cytosolic gate is in the open state. The voltage dependence of the rate constant of blocker release is used to test, which blockers bind to the same binding site. |
| format | Article |
| id | doaj-art-0764decc6bba4b45ac157ac441b73165 |
| institution | Kabale University |
| issn | 1933-6950 1933-6969 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | Channels |
| spelling | doaj-art-0764decc6bba4b45ac157ac441b731652024-12-09T07:27:27ZengTaylor & Francis GroupChannels1933-69501933-69692024-12-0118110.1080/19336950.2024.2402749Binding kinetics of quaternary ammonium ions in Kcv potassium channelsTobias Korn0Ulf-Peter Hansen1Tobias Sebastian Gabriel2Oliver Rauh3Nils Drexler4Indra Schroeder5Plant Membrane Biophysics, Technische Universität Darmstadt, Darmstadt, GermanyDepartment of Structural Biology, Christian-Albrechts-University, Kiel, GermanyPlant Membrane Biophysics, Technische Universität Darmstadt, Darmstadt, GermanyPlant Membrane Biophysics, Technische Universität Darmstadt, Darmstadt, GermanyPhysiology II, University Hospital Jena, Friedrich Schiller University, Jena, GermanyPlant Membrane Biophysics, Technische Universität Darmstadt, Darmstadt, GermanyKcv channels from plant viruses represent the autonomous pore module of potassium channels, devoid of any regulatory domains. These small proteins show very reproducible single-channel behavior in planar lipid bilayers. Thus, they are an optimum system for the study of the biophysics of ion transport and gating. Structural models based on homology modeling have been used successfully, but experimental structural data are currently not available. Here we determine the size of the cytosolic pore entrance by studying the blocker kinetics. Blocker binding and dissociation rate constants ranging from 0.01 to 1000 ms−1 were determined for different quaternary ammonium ions. We found that the cytosolic pore entrance of KcvNTS must be at least 11 Å wide. The results further indicate that the residues controlling a cytosolic gate in one of the Kcv isoforms influence blocker binding/dissociation as well as a second gate even when the cytosolic gate is in the open state. The voltage dependence of the rate constant of blocker release is used to test, which blockers bind to the same binding site.https://www.tandfonline.com/doi/10.1080/19336950.2024.2402749Fast blockviral potassium channeldiffusion limitationblockerplanar lipid bilayersingle-channel currents |
| spellingShingle | Tobias Korn Ulf-Peter Hansen Tobias Sebastian Gabriel Oliver Rauh Nils Drexler Indra Schroeder Binding kinetics of quaternary ammonium ions in Kcv potassium channels Channels Fast block viral potassium channel diffusion limitation blocker planar lipid bilayer single-channel currents |
| title | Binding kinetics of quaternary ammonium ions in Kcv potassium channels |
| title_full | Binding kinetics of quaternary ammonium ions in Kcv potassium channels |
| title_fullStr | Binding kinetics of quaternary ammonium ions in Kcv potassium channels |
| title_full_unstemmed | Binding kinetics of quaternary ammonium ions in Kcv potassium channels |
| title_short | Binding kinetics of quaternary ammonium ions in Kcv potassium channels |
| title_sort | binding kinetics of quaternary ammonium ions in kcv potassium channels |
| topic | Fast block viral potassium channel diffusion limitation blocker planar lipid bilayer single-channel currents |
| url | https://www.tandfonline.com/doi/10.1080/19336950.2024.2402749 |
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