リン酸化とATP結合によるCFTRの適合変化
Zhe Zhang1, Fangyu Liu2, Jue Chen1
1Laboratory of Membrane Biophysics and Biology, The Rockefeller University, New York, NY, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
Cell
|July 25, 2017
まとめ
胞性線維症の膜伝導性調節器 (CFTR) の構造的な洞察は,リン酸化とATP結合がどのように主要な再配置を引き起こし,チャネルを開くかを明らかにする. 細胞外孔口は閉ざされていて,イオン流の局所的な制御を示唆しています.
科学分野:
- 構造生物学
- 分子生物物理学
- イオンチャネル機能
背景:
- 胞性線維症トランスメブラン伝導調節器 (CFTR) は,ATP結合カセットトランスポーターから派生した重要なアニオンチャネルである.
- CFTRチャネルゲーティングは,固有のリン酸化とATPの水解に関連しています.
- 以前の研究では,ATP のない非酸化状態でのCFTRの構造が明らかになった.
研究 の 目的:
- ゼブラフィッシュのCFTRのATPに結合した酸化構造の冷凍EM構造を決定する.
- CFTRチャネル開通に関連した構造的再配置を解明する.
- CFTRにおけるイオン浸透のメカニズムを理解する.
主な方法:
- 構造を決定するために,冷凍電子顕微鏡 (cryo-EM) が使用されました.
- 高解像度構造の決定は3.4 Å解像度で達成されました.
- 異なるCFTR構造の比較分析
主要な成果:
- リン酸化調節ドメインは抑制状態から解離する.
- 核酸結合ドメイン (NBD) は,ATP結合時にヘッド・トゥ・テイル・ダイマーを形成する.
- 他のABCトランスポーターとは異なり,細胞外孔口は閉まっている.
結論:
- リン酸化とATP結合は,CFTRチャネルの開通を容易にする重要な構造的変化を誘導する.
- 独特の構造的な再編成はCFTRの独特のチャネル機能を強調しています.
- 透膜ヘリクスの局所的な動きは,NBDが二元化されている場合でも,孔へのイオンアクセスを調節する可能性があります.
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