3IGA

Potassium Channel KcsA-Fab complex in Li+ and K+

3IGA の概要

• エントリーDOI: 10.2210/pdb3iga/pdb
• 関連するPDBエントリー: 3GB7
• 分子名称: Antibody Fab Fragment heavy chain, Antibody Fab fragment light chain, Voltage-gated potassium channel, ... (6 entities in total)
• 機能のキーワード: kcsa, lithium, lithium block, potassium channel, membrane protein, cell membrane, ion transport, ionic channel, membrane, transmembrane, transport, voltage-gated channel, transport protein
• 由来する生物種: Streptomyces lividans; 詳細
• 細胞内の位置: Cell membrane; Multi-pass membrane protein: P0A334
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 60742.27

構造登録者

Thompson, A.N.,Ilsoo, K.,Panosian, T.D.,Iverson, T.M.,Allen, T.W.,Nimigean, C.M. (登録日: 2009-07-27, 公開日: 2009-11-17, 最終更新日: 2024-10-09)

主引用文献

Thompson, A.N.,Kim, I.,Panosian, T.D.,Iverson, T.M.,Allen, T.W.,Nimigean, C.M.
Mechanism of potassium-channel selectivity revealed by Na(+) and Li(+) binding sites within the KcsA pore.
Nat.Struct.Mol.Biol., 16:1317-1324, 2009

PubMed Abstract: Potassium channels allow K(+) ions to diffuse through their pores while preventing smaller Na(+) ions from permeating. Discrimination between these similar, abundant ions enables these proteins to control electrical and chemical activity in all organisms. Selection occurs at the narrow selectivity filter containing structurally identified K(+) binding sites. Selectivity is thought to arise because smaller ions such as Na(+) do not bind to these K(+) sites in a thermodynamically favorable way. Using the model K(+) channel KcsA, we examined how intracellular Na(+) and Li(+) interact with the pore and the permeant ions using electrophysiology, molecular dynamics simulations and X-ray crystallography. Our results suggest that these small cations have a separate binding site within the K(+) selectivity filter. We propose that selective permeation from the intracellular side primarily results from a large energy barrier blocking filter entry for Na(+) and Li(+) in the presence of K(+), not from a difference of binding affinity between ions.

PubMed: 19946269
DOI: 10.1038/nsmb.1703

実験手法

X-RAY DIFFRACTION (2.75 Å)