6W0B

Open-gate KcsA soaked in 2 mM BaCl2

6W0B の概要

• エントリーDOI: 10.2210/pdb6w0b/pdb
• 分子名称: Fab Heavy Chain, Fab Light Chain, pH-gated potassium channel KcsA, ... (6 entities in total)
• 機能のキーワード: ion channel, membrane protein
• 由来する生物種: Rattus norvegicus; 詳細
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 56749.70

構造登録者

Rohaim, A.,Gong, L.,Li, J. (登録日: 2020-02-29, 公開日: 2020-07-08, 最終更新日: 2024-10-23)

主引用文献

Rohaim, A.,Gong, L.,Li, J.,Rui, H.,Blachowicz, L.,Roux, B.
Open and Closed Structures of a Barium-Blocked Potassium Channel.
J.Mol.Biol., 432:4783-4798, 2020

PubMed Abstract: Barium (Ba) is a classic permeant blocker of potassium (K) channels. The "external lock-in effect" in barium block experiments, whereby the binding of external K impedes the forward translocation of the blocker, provides a powerful avenue to investigate the selectivity of the binding sites along the pore of potassium channels. Barium block experiments show that the external lock-in site is highly selective for K over Na. Wild-type KcsA was crystallized in low K conditions, and the crystals were soaked in solutions containing various concentrations of barium. Structural analysis reveals open and closed gate conformations of the KcsA channel. Anomalous diffraction experiments show that Ba primarily binds to the innermost site S4 of the selectivity filter of the open-gate conformation and also the site S2, but no binding is detected with the closed-gate conformation. Alchemical free-energy perturbation calculations indicate that the presence of a Ba ion in the selectivity filter boosts the specificity of K binding relative to Na in the external sites S0-S2.

PubMed: 32615129
DOI: 10.1016/j.jmb.2020.06.012

実験手法

X-RAY DIFFRACTION (3.604 Å)