3AT9

Crystal Structure of the Kir3.2 Cytoplasmic Domain (Na+-free crystal soaked in 10 mM barium chloride and 10 mM magnesium chloride)

3AT9 の概要

• エントリーDOI: 10.2210/pdb3at9/pdb
• 関連するPDBエントリー: 2e4f 3AT8 3ATA 3ATB 3ATD 3ATE 3ATF 3agw
• 分子名称: Potassium inwardly-rectifying channel, subfamily J, member 6, MAGNESIUM ION (2 entities in total)
• 機能のキーワード: cytoplasmic assembly, beta-barrel, ion transport, g protein beta-gamma subunits, transport protein
• 由来する生物種: Mus musculus (mouse); 詳細
• 細胞内の位置: Membrane ; Multi-pass membrane protein : Q0VB45
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 23773.29

構造登録者

Inanobe, A.,Kurachi, Y. (登録日: 2010-12-28, 公開日: 2011-10-19, 最終更新日: 2024-03-13)

主引用文献

Inanobe, A.,Nakagawa, A.,Kurachi, Y.
Interactions of cations with the cytoplasmic pores of inward rectifier K(+) channels in the closed state
J.Biol.Chem., 286:41801-41811, 2011

PubMed Abstract: Ion channels gate at membrane-embedded domains by changing their conformation along the ion conduction pathway. Inward rectifier K(+) (Kir) channels possess a unique extramembrane cytoplasmic domain that extends this pathway. However, the relevance and contribution of this domain to ion permeation remain unclear. By qualitative x-ray crystallographic analysis, we found that the pore in the cytoplasmic domain of Kir3.2 binds cations in a valency-dependent manner and does not allow the displacement of Mg(2+) by monovalent cations or spermine. Electrophysiological analyses revealed that the cytoplasmic pore of Kir3.2 selectively binds positively charged molecules and has a higher affinity for Mg(2+) when it has a low probability of being open. The selective blocking of chemical modification of the side chain of pore-facing residues by Mg(2+) indicates that the mode of binding of Mg(2+) is likely to be similar to that observed in the crystal structure. These results indicate that the Kir3.2 crystal structure has a closed conformation with a negative electrostatic field potential at the cytoplasmic pore, the potential of which may be controlled by conformational changes in the cytoplasmic domain to regulate ion diffusion along the pore.

PubMed: 21982822
DOI: 10.1074/jbc.M111.278531

実験手法

X-RAY DIFFRACTION (3.3 Å)