チャペロニンタンパク質であるGroELとGroESの核酸結合領域の特定
J Martin1, S Geromanos, P Tempst
1Cellular Biochemistry and Biophysics Program, Memorial Sloan-Kettering Cancer Center, New York 10021.
Nature
|November 18, 1993
まとめ
チャペロニンGroEL-GroESシステムは,E. coliのタンパク質の折り畳みを促進する. この研究では,GroESはATPも結合し,GroELにとって決定的な役割を果たしている可能性があることが明らかになりました.
科学分野:
- 分子生物学は分子生物学である.
- タンパク質の折り畳みメカニズム
- バイオケミストリー バイオケミストリー
背景:
- チャペロニンGroELとそのコファクターGroESは,Escherichia coliにおけるタンパク質の折り畳みに不可欠である.
- それらは,展開されたタンパク質を結合する複合体を形成し,ATP水解で折りたたむための放出を促進します.
研究 の 目的:
- GroELとGroESのサブユニット内のヌクレオチド結合ドメインを識別する.
- GroEL-GroESのタンパク質折りたたみ装置におけるヌクレオチド結合の役割を調査する.
主な方法:
- サイト指向型変異およびアジド-ATPによるタンパク質のラベル付け.
- プロテアゼの安定性測定は,核酸結合ドメインを特定するために行われます.
- GroESにおけるATP結合親和性と協同性の分析.
主要な成果:
- GroELでは,アジド-ATPがTyr 477にクロスリンクした,プロテアゼ安定型核酸結合ドメイン (残留153-531) が特定されました.
- GroESは,GroELに匹敵する親和性でATPを協力的に結合することが判明しました.
- GroESのアジドヌクレオチドラベル付けは,安定した6.5K領域のTyr 71で発生し,GroESがGroELに結合すると,残基32での割れが防止されました.
結論:
- GroELサブユニットには,その機能に不可欠な特定の核酸結合ドメインが含まれています.
- また,GroESはATPを結合するので,単なる蓋の役割を超えて,より複雑な役割があることを示唆しています.
- GroESへのATP結合は,効率的なATP結合と水解のためにGroELリングをプライムし,基質タンパク質の放出と折り畳みを最適化することができます.
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