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酵母タンパク質二硫化イソメラーゼの本質的な機能は,そのイソメラーゼ活性にはない
1Department of Biochemistry and Cell Biology, State University of New York at Stony Brook 11794-5215.
Cell
|September 10, 1993
まとめ
タンパク質二硫酸イソメラーゼ (PDI) は,二硫酸結合形成を触媒化することによって,タンパク質の折り畳みを促進する. イーストの生命力にとって不可欠ですが,PDIの触媒作用は厳格には必要ではなく,タンパク質の折り畳みのための代替経路を示唆しています.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- イースト遺伝学 イースト遺伝学
背景:
- タンパク質二硫化異体酵素 (PDI) は,二硫化結合異体化を触媒化し,タンパク質の折りたたみを支援するために不可欠です.
- PDIは,Saccharomyces cerevisiaeの重要な遺伝子によってコードされ,細胞プロセスにおけるその重要性を強調しています.
研究 の 目的:
- PDIのインビヴォ機能,特にその活性部位が触媒と細胞生存能力における役割を調査する.
- PDIの触媒作用が酵母細胞の生存に不可欠かどうかを判断する.
主な方法:
- S. cerevisiaeにおけるPDIの遺伝子操作は,C端末の削除と活性部位モチーフ (CGHC) の破壊を含む.
- PDIの触媒活性を評価するためのインビトロ酵素測定法.
- 改変酵母菌株における細胞の局所化,細胞活力,タンパク質輸送 (カルボキシペプチダゼY) の分析.
主要な成果:
- PDIのC端末残留物の削除は局所を変化させたが,活性を変化させなかった;さらなる削除は,in vitro活性が保持されているにもかかわらず致命的であった.
- 両方のCGHC活性部位の破壊はPDIを in vitroで触媒的に無効にしたが,致死性を引き起こさなかった.
- 触媒的に不活性なPDIを有する酵母細胞は,二硫化結合形成の遅延とカルボキシペプチダゼY輸送を示した.
結論:
- PDIは,in vitroとin vivoの両方で二酸化硫化物結合形成を触媒化し,触媒化には完全な活性部位を必要とします.
- PDIの触媒的活動は酵母生存に不可欠ではないが,タンパク質の折りたたみに対する潜在的な補償メカニズムを示している.
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