Selectivity and permeation of alkali metal ions in K +-channels
Ion conduction in K +-channels is usually described in terms of concerted movements of K + progressing in a single file through a narrow pore. Permeation is driven by an incoming ion knocking on those ions already inside the protein. A fine-tuned balan...
| Main Authors: | , |
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| Format: | Journal article |
| Language: | English |
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2011
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| _version_ | 1826258046066622464 |
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| author | Furini, S Domene, C |
| author_facet | Furini, S Domene, C |
| author_sort | Furini, S |
| collection | OXFORD |
| description | Ion conduction in K +-channels is usually described in terms of concerted movements of K + progressing in a single file through a narrow pore. Permeation is driven by an incoming ion knocking on those ions already inside the protein. A fine-tuned balance between high-affinity binding and electrostatic repulsive forces between permeant ions is needed to achieve efficient conduction. While K +-channels are known to be highly selective for K + over Na +, some K + channels conduct Na + in the absence of K +. Other ions are known to permeate K +-channels with a more moderate preference and unusual conduction features. We describe an extensive computational study on ion conduction in K +-channels rendering free energy profiles for the translocation of three different alkali ions and some of their mixtures. The free energy maps for Rb + translocation show at atomic level why experimental Rb + conductance is slightly lower than that of K +. In contrast to K + or Rb +, external Na + block K + currents, and the sites where Na + transport is hindered are characterized. Translocation of K +/Na + mixtures is energetically unfavorable owing to the absence of equally spaced ion-binding sites for Na +, excluding Na + from a channel already loaded with K +. © 2011 Elsevier Ltd. All rights reserved. |
| first_indexed | 2024-03-06T18:27:49Z |
| format | Journal article |
| id | oxford-uuid:0896e38c-f59f-446f-b952-743f8e689867 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T18:27:49Z |
| publishDate | 2011 |
| record_format | dspace |
| spelling | oxford-uuid:0896e38c-f59f-446f-b952-743f8e6898672022-03-26T09:13:39ZSelectivity and permeation of alkali metal ions in K +-channelsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:0896e38c-f59f-446f-b952-743f8e689867EnglishSymplectic Elements at Oxford2011Furini, SDomene, CIon conduction in K +-channels is usually described in terms of concerted movements of K + progressing in a single file through a narrow pore. Permeation is driven by an incoming ion knocking on those ions already inside the protein. A fine-tuned balance between high-affinity binding and electrostatic repulsive forces between permeant ions is needed to achieve efficient conduction. While K +-channels are known to be highly selective for K + over Na +, some K + channels conduct Na + in the absence of K +. Other ions are known to permeate K +-channels with a more moderate preference and unusual conduction features. We describe an extensive computational study on ion conduction in K +-channels rendering free energy profiles for the translocation of three different alkali ions and some of their mixtures. The free energy maps for Rb + translocation show at atomic level why experimental Rb + conductance is slightly lower than that of K +. In contrast to K + or Rb +, external Na + block K + currents, and the sites where Na + transport is hindered are characterized. Translocation of K +/Na + mixtures is energetically unfavorable owing to the absence of equally spaced ion-binding sites for Na +, excluding Na + from a channel already loaded with K +. © 2011 Elsevier Ltd. All rights reserved. |
| spellingShingle | Furini, S Domene, C Selectivity and permeation of alkali metal ions in K +-channels |
| title | Selectivity and permeation of alkali metal ions in K
+-channels |
| title_full | Selectivity and permeation of alkali metal ions in K
+-channels |
| title_fullStr | Selectivity and permeation of alkali metal ions in K
+-channels |
| title_full_unstemmed | Selectivity and permeation of alkali metal ions in K
+-channels |
| title_short | Selectivity and permeation of alkali metal ions in K
+-channels |
| title_sort | selectivity and permeation of alkali metal ions in k channels |
| work_keys_str_mv | AT furinis selectivityandpermeationofalkalimetalionsinkchannels AT domenec selectivityandpermeationofalkalimetalionsinkchannels |