ヘテロディメリックABCエクスポーターにおける大規模コンフォームトランジションの原子化メカニズム
Hendrik Göddeke1, M Hadi Timachi2, Cedric A J Hutter3
1Theoretical Chemistry, Faculty of Chemistry and Biochemistry , Ruhr-University Bochum , 44780 Bochum , Germany.
Journal of the American Chemical Society
|March 17, 2018
まとめ
この研究はATP結合カセット (ABC) トランスポーターTM287/288の原子機構を明らかにした. ATP結合が構造変化を駆動し,トランスポーターを内向きから外向きの状態に遮断された中間体を通して移動させることを示しています.
科学分野:
- 構造生物学
- 生物化学
- 分子生物物理学
背景:
- ATP結合カセット (ABC) トランスポーターは,ATP結合と水解を基板転位に使用する.
- ヌクレオチド結合ドメイン (NBDs) とトランスメブランドメイン (TMDs) の間のダイナミックカップリングは,まだ十分に理解されていません.
- これらのダイナミクスを理解することは,膜輸送のメカニズムを明らかにするために不可欠です.
研究 の 目的:
- ABCエクスポーターTM287/288における構成変異の原子レベルメカニズムを解明する.
- 原子解像度で隠された状態と外向きの状態を特徴付けます.
- 輸送サイクル中のNBDとTMDの動きの結合を調査する.
主な方法:
- 全原子分子ダイナミクス (MD) シミュレーション
- 電子パラマグネティック共振 (EPR) スペクトロスコーピー
- 複数のマイクロ秒で明示的な膜/水環境で実行されたシミュレーション.
主要な成果:
- TM287/288は,ATP結合時にオークルデッド (Occ) の中間体を通して,内向き (IF) から外向き (OF) の状態に移行する.
- ATP結合は,NBDジメールの引き締まりと細胞内TMDゲートの閉塞を誘導し,Occ状態を形成する.
- 以降の細胞外TMDゲート開きは,ゲートが同時に開かないOF状態につながります.
結論:
- TM287/288の構成サイクルに関する詳細な原子メカニズムが提案されている.
- NBD-TMDカップリングは,協調ドメインとTMD内の構成変化によって達成されます.
- この研究は,異種ABC輸出者の機能的な作業サイクルに関する原子レベルの洞察を提供します.
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