The isolated voltage sensing domain of the Shaker potassium channel forms a voltage-gated cation channel

Domains in macromolecular complexes are often considered structurally and functionally conserved while energetically coupled to each other. In the modular voltage-gated ion channels the central ion-conducting pore is surrounded by four voltage sensing domains (VSDs). Here, the energetic coupling is...

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Main Authors: Juan Zhao, Rikard Blunck
Format: Article
Language:English
Published: eLife Sciences Publications Ltd 2016-10-01
Series:eLife
Subjects:
Online Access:https://elifesciences.org/articles/18130
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author Juan Zhao
Rikard Blunck
author_facet Juan Zhao
Rikard Blunck
author_sort Juan Zhao
collection DOAJ
description Domains in macromolecular complexes are often considered structurally and functionally conserved while energetically coupled to each other. In the modular voltage-gated ion channels the central ion-conducting pore is surrounded by four voltage sensing domains (VSDs). Here, the energetic coupling is mediated by interactions between the S4-S5 linker, covalently linking the domains, and the proximal C-terminus. In order to characterize the intrinsic gating of the voltage sensing domain in the absence of the pore domain, the Shaker Kv channel was truncated after the fourth transmembrane helix S4 (Shaker-iVSD). Shaker-iVSD showed significantly altered gating kinetics and formed a cation-selective ion channel with a strong preference for protons. Ion conduction in Shaker-iVSD developed despite identical primary sequence, indicating an allosteric influence of the pore domain. Shaker-iVSD also displays pronounced 'relaxation'. Closing of the pore correlates with entry into relaxation suggesting that the two processes are energetically related.
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spelling doaj.art-347daba172fd4b8c823d33463c8e7b812022-12-22T03:52:43ZengeLife Sciences Publications LtdeLife2050-084X2016-10-01510.7554/eLife.18130The isolated voltage sensing domain of the Shaker potassium channel forms a voltage-gated cation channelJuan Zhao0Rikard Blunck1https://orcid.org/0000-0003-4484-2907Department of Physics, Université de Montréal, Montréal, Canada; Department of Pharmacology and Physiology, Université de Montréal, Montréal, CanadaDepartment of Physics, Université de Montréal, Montréal, Canada; Department of Pharmacology and Physiology, Université de Montréal, Montréal, CanadaDomains in macromolecular complexes are often considered structurally and functionally conserved while energetically coupled to each other. In the modular voltage-gated ion channels the central ion-conducting pore is surrounded by four voltage sensing domains (VSDs). Here, the energetic coupling is mediated by interactions between the S4-S5 linker, covalently linking the domains, and the proximal C-terminus. In order to characterize the intrinsic gating of the voltage sensing domain in the absence of the pore domain, the Shaker Kv channel was truncated after the fourth transmembrane helix S4 (Shaker-iVSD). Shaker-iVSD showed significantly altered gating kinetics and formed a cation-selective ion channel with a strong preference for protons. Ion conduction in Shaker-iVSD developed despite identical primary sequence, indicating an allosteric influence of the pore domain. Shaker-iVSD also displays pronounced 'relaxation'. Closing of the pore correlates with entry into relaxation suggesting that the two processes are energetically related.https://elifesciences.org/articles/18130voltage sensorpotassium channelgatingvoltage-clamp fluorometrymode-shift
spellingShingle Juan Zhao
Rikard Blunck
The isolated voltage sensing domain of the Shaker potassium channel forms a voltage-gated cation channel
eLife
voltage sensor
potassium channel
gating
voltage-clamp fluorometry
mode-shift
title The isolated voltage sensing domain of the Shaker potassium channel forms a voltage-gated cation channel
title_full The isolated voltage sensing domain of the Shaker potassium channel forms a voltage-gated cation channel
title_fullStr The isolated voltage sensing domain of the Shaker potassium channel forms a voltage-gated cation channel
title_full_unstemmed The isolated voltage sensing domain of the Shaker potassium channel forms a voltage-gated cation channel
title_short The isolated voltage sensing domain of the Shaker potassium channel forms a voltage-gated cation channel
title_sort isolated voltage sensing domain of the shaker potassium channel forms a voltage gated cation channel
topic voltage sensor
potassium channel
gating
voltage-clamp fluorometry
mode-shift
url https://elifesciences.org/articles/18130
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