S100タンパク質のカルシウム媒介制御:アギテーター/シグナルブロックメカニズムによるアロステリック通信
Yiming Xiao1, Gary S Shaw1, Lars Konermann1
1Department of Chemistry, The University of Western Ontario , London, Ontario N6A 5B7, Canada.
Journal of the American Chemical Society
|August 1, 2017
まとめ
カルシウムイオンはS100A11タンパク質の結合部位の閉塞を阻害し,新しいアロステリックメカニズムを明らかにします. ラビル塩のブリッジは信号伝播を開始し,カルシウム結合を阻害し,従来のアロステリック経路モデルに挑戦します.
科学分野:
- 生物化学
- 構造生物学
- タンパク質ダイナミクス
背景:
- アロステルタンパク質は信号伝達を介して生物学的プロセスを調節する.
- アロステリック調節の正確なメカニズム,特に信号伝播は完全に理解されていません.
- S100A11は,Ca2+調節された標的結合を持つ二重EFハンドタンパク質です.
研究 の 目的:
- S100A11- アネキシンペプチド (Ax) 相互作用のアロステリックメカニズムを解明する.
- S100A11の標的結合部位の開閉を制御する方法を理解する.
- アロステル信号伝播経路における初期イベントを特定する.
主な方法:
- 水中のマイクロ秒分子動力学 (MD) シミュレーション
- 水素-デュテリウム交換質量スペクトロメトリー (HDX/MS)
- タンパク質-Ca2+-ペプチド複合体の計算モデル化
主要な成果:
- S100A11へのCa2+結合は,標的結合部位の閉塞を防止し,開いた状態を維持する.
- Ca2+が存在しない場合,S100A11の標的結合部位は閉ざされ,アネキシンペプチドの相互作用は排除されます.
- メタレーション部位ではなく,ラビル塩ブリッジが,結合部位の閉塞につながるアロステリックシグナルカスケードを開始する.
結論:
- S100A11へのCa2+結合はゲートキーパーとして作用し,主要なタンパク質要素を硬化することによって,アロステル信号伝送を防止します.
- アロステリック経路は,隣接する残留物を不安定化する,不安定な塩橋から発生します.
- このメカニズムは,エフェクタ結合部位で開始されるアロステリック経路に関する従来の見解に異議を唱える.
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