4QE7

Open MthK pore structure soaked in 10 mM Ba2+/100 mM Na+

4QE7 の概要

• エントリーDOI: 10.2210/pdb4qe7/pdb
• 関連するPDBエントリー: 3LDC 3LDD 3LDE 4QE9
• 分子名称: Calcium-gated potassium channel MthK, BARIUM ION (3 entities in total)
• 機能のキーワード: transmembrane, ion channel, open conformation, transport protein
• 由来する生物種: Methanothermobacter thermautotrophicus
• 細胞内の位置: Cell membrane; Multi-pass membrane protein: O27564
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 9347.43

構造登録者

Guo, R.,Zeng, W.,Cui, H.,Chen, L.,Ye, S. (登録日: 2014-05-15, 公開日: 2014-07-09, 最終更新日: 2023-11-08)

主引用文献

Guo, R.,Zeng, W.,Cui, H.,Chen, L.,Ye, S.
Ionic interactions of Ba2+ blockades in the MthK K+ channel
J.Gen.Physiol., 144:193-200, 2014

PubMed Abstract: The movement and interaction of multiple ions passing through in single file underlie various fundamental K(+) channel properties, from the effective conduction of K(+) ions to channel blockade by Ba(2+) ions. In this study, we used single-channel electrophysiology and x-ray crystallography to probe the interactions of Ba(2+) with permeant ions within the ion conduction pathway of the MthK K(+) channel. We found that, as typical of K(+) channels, the MthK channel was blocked by Ba(2+) at the internal side, and the Ba(2+)-blocking effect was enhanced by external K(+). We also obtained crystal structures of the MthK K(+) channel pore in both Ba(2+)-Na(+) and Ba(2+)-K(+) environments. In the Ba(2+)-Na(+) environment, we found that a single Ba(2+) ion remained bound in the selectivity filter, preferably at site 2, whereas in the Ba(2+)-K(+) environment, Ba(2+) ions were predominantly distributed between sites 3 and 4. These ionic configurations are remarkably consistent with the functional studies and identify a molecular basis for Ba(2+) blockade of K(+) channels.

PubMed: 25024268
DOI: 10.1085/jgp.201411192

実験手法

X-RAY DIFFRACTION (2.4 Å)