1JVM

KCSA POTASSIUM CHANNEL WITH TBA (TETRABUTYLAMMONIUM) AND RUBIDIUM

Summary for 1JVM

• Entry DOI: 10.2210/pdb1jvm/pdb
• Related: 1BL8 1J95
• Descriptor: Voltage-gated potassium channel, RUBIDIUM ION, TETRABUTYLAMMONIUM ION, ... (4 entities in total)
• Functional Keywords: membrane protein, potassium channel, metal transport
• Biological source: Streptomyces lividans
• Cellular location: Cell membrane; Multi-pass membrane protein: P0A334
• Total number of polymer chains: 4
• Total formula weight: 53933.89

Authors

Morais-Cabral, J.H.,Zhou, Y.,MacKinnon, R. (deposition date: 2001-08-30, release date: 2001-12-05, Last modification date: 2023-08-16)

Primary citation

Morais-Cabral, J.H.,Zhou, Y.,MacKinnon, R.
Energetic optimization of ion conduction rate by the K+ selectivity filter.
Nature, 414:37-42, 2001

PubMed Abstract: 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.

PubMed: 11689935
DOI: 10.1038/35102000

Experimental method

X-RAY DIFFRACTION (2.8 Å)