単一の負の電荷の残留物に局限した内側を修正するK+チャネルのゲーティング

B A Wible¹, M Taglialatela, E Ficker

¹Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030.

Nature

|September 15, 1994

まとめ

内部修正カリウムチャネル (IRK) は,電圧依存のゲーティングを示す. 単一のアミノ酸変化,M2ドメインのアスパルゲンからアスパルゲンへのアスパルゲンは,この重要なゲーティング現象型を制御します.

科学分野:

分子生物学は分子生物学である.
バイオフィジックス生物物理学
イオンチャネル機能のイオンチャネル機能

背景:

内側を整えるK+チャネル (IRK) はイオン流の方向を制御する.
IRKゲーティングには,電圧に依存するMg2+ブロックと固有のゲーティングメカニズムが含まれています.
IRK1とROMK1は,異なるMg2+の親和性とゲーティング特性を示しています.

研究の目的:

IRKチャネルにおける電圧依存ゲーティングの構造的基礎を調査する.
IRK1とROMK1.1のゲーティングフェノタイプの差異に起因する特定のアミノ酸残基を特定する.

主な方法:

IRKチャネルファミリーのメンバーの大規模なサイト指向型変異.
変異したチャネル構造の電気生理学的分析.
IRK1とROMK1のゲーティング特性の比較研究.

主要な成果:

IRK1のM2領域における単一のアミノ酸置換 (D172N) は,ROMK1のようなゲーティングを与えました.
ROMK1の逆変異 (N171D) は,IRK1のようなゲーティングを引き起こした.
この位置での負の電荷の残留は,IRKゲーティングの決定的な決定因子です.

結論:

IRKチャネルの電圧依存ゲーティングは,M2ドメインの単一のアミノ酸残留物によって制御されます.
この残留物,IRK1のアスパルテートは,チャネルの固有のゲーティング特性を決定する.
この発見は,イオンチャネル機能と調節における特定の電荷残留物の役割を強調しています.

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