DegSストレスセンサーの結晶構造:PDZドメインが誤折りたたまれたタンパク質を認識し,プロテアゼを活性化する方法
Corinna Wilken1, Karina Kitzing, Robert Kurzbauer
1Institute for Molecular Pathology (IMP), Dr. Bohrgasse 7, A-1030 Vienna, Austria.
Cell
|May 13, 2004
まとめ
細菌のストレス反応に不可欠なDegSプロテアゼは,そのPDZドメインに結合するストレスシグナルペプチドによって活性化されます. この結合は構造変化を引き起こし,プロテアゼの機能と可逆活性化を可能にします.
科学分野:
- 微生物学 微生物学とは
- 構造生物学 構造生物学とは
- バイオケミストリー バイオケミストリー
背景:
- グラム陰性細菌は,シグマE経路を利用して,細胞封筒内の間違った折りたたまれたタンパク質を管理します.
- DegSプロテアゼは,RseAアンチシグマ因子を分裂させることで,sigmaEを活性化するために不可欠なプロテオリートカスケードを開始します.
研究 の 目的:
- ストレスシグナリングペプチドによるDegSプロテアゼ活性化に伴う構造的メカニズムを解明する.
- 周辺プラズマ的ストレスを感知し,プロテアゼ活性を調節するPDZドメインの役割を調査する.
主な方法:
- X線結晶学を使用して,E. coli DegS.の3つの異なる状態の構造を決定しました.
- 単独のDegS,活性化ペプチドに結合したDegS,およびハイブリッドの活性/無活性状態の分析.
主要な成果:
- DegSは,アクティベータがない場合,触媒的に不活性な形で存在します.
- ストレスシグナリングペプチドがPDZドメインに結合すると,DegSを活性化する形状の変化が生じます.
- 構造分析により,活性/無活性ハイブリッド状態を含む可逆的な活性化メカニズムが明らかになった.
結論:
- DegSは,ペプチド結合をプロテアゼ活性化に変換する,ペリプラズマのストレスセンサーとして機能します.
- PDZドメインは,タンパク質酵素活性化における新たな規制的役割を果たします.
- 細胞ストレスへの反応として,可逆性プロテアゼ活性化のための新しいメカニズムが特定されました.
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