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Measuring Nucleotide Binding to Intact, Functional Membrane Proteins in Real Time
Published on: March 11, 2021
Mapping the sequence of conformational changes underlying selectivity filter gating in the K(v)11.1 potassium channel
David T Wang1, Adam P Hill, Stefan A Mann
1Mark Cowley Lidwill Research Program in Cardiac Electrophysiology, Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, New South Wales, Australia. j.vandenberg@victorchang.edu.au
Nature Structural & Molecular Biology
|December 21, 2010
Summary
Potassium channel gating involves complex domain movements. In the human K(v)11.1 channel (hERG), K(+) exit triggers sequential rearrangements, unlike simpler models for ligand-gated channels.
Area of Science:
- Biophysics
- Molecular Biology
- Cardiology
Background:
- Potassium channels are crucial for cellular electrical activity.
- The selectivity filter of potassium channels distinguishes ions and controls flow.
- Known structures represent open and closed states, but the transition is unclear.
Purpose of the Study:
- To elucidate the sequence of protein rearrangements during selectivity filter gate closure in the human K(v)11.1 K(+) channel (hERG).
- To compare the gating mechanism of hERG channels with models for ligand-gated ion channels.
Main Methods:
- The study likely involved electrophysiology and structural biology techniques to observe channel dynamics.
- Analysis focused on the human K(v)11.1 K(+) channel, a critical regulator of heart rhythm.
Main Results:
- Potassium ion (K(+)) exit initiates selectivity filter gate closure.
- This is followed by a specific sequence of conformational changes in the pore domain outer helix, extracellular turret, voltage sensor domain, and intracellular domains.
- The process involves complex, widespread domain motions, not a simple wave-like progression.
Conclusions:
- The transition between open and inactivated states of the K(v)11.1 channel is governed by a complex, multi-domain mechanism.
- This mechanism differs significantly from the proposed gating sequences in ligand-gated ion channels.
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