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Energetic optimization of ion conduction rate by the K + selectivity filter

MacKinnon, Roderick ; Morais-Cabral, João H ; Zhou, Yufeng

Nature, 2001-11, Vol.414 (6859), p.37-42 [Periódico revisado por pares]

London: Nature Publishing

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Título:
Energetic optimization of ion conduction rate by the K + selectivity filter
Autor: MacKinnon, Roderick ; Morais-Cabral, João H ; Zhou, Yufeng
Assuntos: Bacterial Proteins ; Binding Sites ; Biochemistry ; Biological and medical sciences ; Cell membranes. Ionic channels. Membrane pores ; Cell structures and functions ; Crystallography, X-Ray ; Diffusion ; Electrochemistry ; FILTERS ; Fundamental and applied biological sciences. Psychology ; GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE ; Ion Transport ; Ions ; Kinetics ; Molecular and cellular biology ; NATIONAL SYNCHROTRON LIGHT SOURCE ; NSLS ; OPTIMIZATION ; Particle Size ; Potassium ; Potassium - chemistry ; Potassium - metabolism ; Potassium Channels - chemistry ; Potassium Channels - metabolism ; Proteins ; Rubidium - chemistry ; Rubidium - metabolism ; Water - chemistry ; Water - metabolism
É parte de: Nature, 2001-11, Vol.414 (6859), p.37-42
Notas: ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ObjectType-Article-2
ObjectType-Feature-1
AC02-98CH10886
USDOE Office of Energy Research (ER) (US)
Descrição: 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.
Editor: London: Nature Publishing
Idioma: Inglês

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Energetic optimization of ion conduction rate by the K + selectivity filter

MacKinnon, Roderick ; Morais-Cabral, João H ; Zhou, Yufeng

London: Nature Publishing

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