GroEL作用のメカニズム:GroESの下で隔離された位置からポリペプチドの生産的な放出
J S Weissman1, C M Hohl, O Kovalenko
1Department of Genetics, Yale School of Medicine New Haven, Connecticut 06510, USA.
Cell
|November 17, 1995
まとめ
チャペロニンGroEL-GroESシステムは,2段階のメカニズムでタンパク質の折り畳みを支援します. GroESはタンパク質を封じ込め,ATPの水解はそれらの放出と生産的な折り畳みを促します.
科学分野:
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
- タンパク質の折りたたみ
背景:
- チャペロニンGroELは,コチャペロニンGroESとATPとともに,タンパク質の折り畳みをin vivoで促進する.
- GroELは二重環構造であり,GroESは1つのGroEL環に不対称に結合する.
研究 の 目的:
- GroEL-GroES媒介のタンパク質折り畳みのメカニズムを解明する.
- GroEL複合体内のポリペプチド結合と放出ダイナミクスを調査する.
主な方法:
- ポリペプチド結合部位を特定するためのクロスリンク研究.
- オルニチントランスカルバミラーゼを用いたシングルターンオーバー実験.
- GroEL-GroES複合体の形成と解離の分析.
主要な成果:
- ポリペプチド結合は,GroES (トランス複合体) が占有していないGroELリングで起こります.
- 放出されたGroESは,ポリペプチド (cis複合体) を含むGroELリングに再結合することができます.
- ポリペプチドは,ADPを持つcis複合体で保護され,transではなくcis複合体から生産的に放出されます.
結論:
- GroELによる折り畳みの2段階メカニズムが提案されています.
- ステップ1:GroESは,GroEL腔内にあるポリペプチドを異動させ,隔離する.
- ステップ2:ATPの水解がGroESの放出と生産性ポリペプチドの放出を誘発する.
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