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Membrane Anchoring and Interaction between Transmembrane Domains are Crucial for K+ Channel Function.

Gebhardt, Manuela and Hoffgaard, Franziska and Hamacher, Kay and Kast, S. M. and Moroni, Anna and Thiel, Gerhard (2011):
Membrane Anchoring and Interaction between Transmembrane Domains are Crucial for K+ Channel Function.
In: The Journal of biological chemistry, pp. 11299-306, 286, (13), ISSN 1083-351X,
[Article]

Abstract

The small viral channel Kcv is a Kir-like K(+) channel of only 94 amino acids. With this simple structure, the tetramer of Kcv represents the pore module of all complex K(+) channels. To examine the structural contribution of the transmembrane domains (TMDs) to channel function, we performed Ala scanning mutagenesis of the two domains and tested the functionality of the mutants in a yeast complementation assay. The data reveal, in combination with computational models, that the upper halves of both TMDs, which face toward the external medium, are rather rigid, whereas the inner parts are more flexible. The rigidity of the outer TMD is conferred by a number of essential aromatic amino acids that face the membrane and probably anchor this domain in the bilayer. The inner TMD is intimately connected with the rigid part of the outer TMD via π···π interactions between a pair of aromatic amino acids. This structural principle is conserved within the viral K(+) channels and also present in Kir2.2, implying a general importance of this architecture for K(+) channel function.

Item Type: Article
Erschienen: 2011
Creators: Gebhardt, Manuela and Hoffgaard, Franziska and Hamacher, Kay and Kast, S. M. and Moroni, Anna and Thiel, Gerhard
Title: Membrane Anchoring and Interaction between Transmembrane Domains are Crucial for K+ Channel Function.
Language: English
Abstract:

The small viral channel Kcv is a Kir-like K(+) channel of only 94 amino acids. With this simple structure, the tetramer of Kcv represents the pore module of all complex K(+) channels. To examine the structural contribution of the transmembrane domains (TMDs) to channel function, we performed Ala scanning mutagenesis of the two domains and tested the functionality of the mutants in a yeast complementation assay. The data reveal, in combination with computational models, that the upper halves of both TMDs, which face toward the external medium, are rather rigid, whereas the inner parts are more flexible. The rigidity of the outer TMD is conferred by a number of essential aromatic amino acids that face the membrane and probably anchor this domain in the bilayer. The inner TMD is intimately connected with the rigid part of the outer TMD via π···π interactions between a pair of aromatic amino acids. This structural principle is conserved within the viral K(+) channels and also present in Kir2.2, implying a general importance of this architecture for K(+) channel function.

Journal or Publication Title: The Journal of biological chemistry
Volume: 286
Number: 13
Uncontrolled Keywords: Bioinformatik
Divisions: 10 Department of Biology
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10 Department of Biology > Plant Membrane Biophysics
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10 Department of Biology > Computational Biology and Simulation
20 Department of Computer Science
Date Deposited: 27 Apr 2011 08:13
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