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1jvm
From Proteopedia
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[[Image:1jvm.gif|left|200px]] | [[Image:1jvm.gif|left|200px]] | ||
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'''KCSA POTASSIUM CHANNEL WITH TBA (TETRABUTYLAMMONIUM) AND RUBIDIUM''' | '''KCSA POTASSIUM CHANNEL WITH TBA (TETRABUTYLAMMONIUM) AND RUBIDIUM''' | ||
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[[Category: Morais-Cabral, J H.]] | [[Category: Morais-Cabral, J H.]] | ||
[[Category: Zhou, Y.]] | [[Category: Zhou, Y.]] | ||
| - | [[Category: | + | [[Category: Membrane protein]] |
| - | [[Category: | + | [[Category: Metal transport]] |
| - | [[Category: | + | [[Category: Potassium channel]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 21:58:49 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 18:58, 2 May 2008
KCSA POTASSIUM CHANNEL WITH TBA (TETRABUTYLAMMONIUM) AND RUBIDIUM
Overview
The K+ selectivity filter catalyses the dehydration, transfer and rehydration of a K+ ion in about ten nanoseconds. This physical process is central to the production of electrical signals in biology. Here we show how nearly diffusion-limited rates are achieved, by analysing ion conduction and the corresponding crystallographic ion distribution in the selectivity filter of the KcsA K+ channel. Measurements with K+ and its slightly larger analogue, Rb+, lead us to conclude that the selectivity filter usually contains two K+ ions separated by one water molecule. The two ions move in a concerted fashion between two configurations, K+-water-K+-water (1,3 configuration) and water-K+-water-K+ (2,4 configuration), until a third ion enters, displacing the ion on the opposite side of the queue. For K+, the energy difference between the 1,3 and 2,4 configurations is close to zero, the condition of maximum conduction rate. The energetic balance between these configurations is a clear example of evolutionary optimization of protein function.
About this Structure
1JVM is a Single protein structure of sequence from Streptomyces lividans. Full crystallographic information is available from OCA.
Reference
Energetic optimization of ion conduction rate by the K+ selectivity filter., Morais-Cabral JH, Zhou Y, MacKinnon R, Nature. 2001 Nov 1;414(6859):37-42. PMID:11689935 Page seeded by OCA on Fri May 2 21:58:49 2008
