ネイティブのUre2pからアミロイド形成のプリオン領域のイニシアチブ in vitro
K L Taylor1, N Cheng, R W Williams
1Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA.
まとめ
酵母中の[URE3]プリオンは,Ure2pタンパク質のアミロイドフィラメントの自己拡散によって説明されます. これらのアミロイド構造は,Ure2pの断片によって形成され,ネイティブUre2pのポリメリゼーションを誘導し,プリオン行動を模倣することができます.
科学分野:
- 分子生物学は分子生物学である.
- タンパク質の生化学
- イースト遺伝学 イースト遺伝学
背景:
- Saccharomyces cerevisiae の [URE3] 要素は,メンデルの型ではない遺伝因子である.
- Ure2pタンパク質の伝染性プリオン形態であり,窒素分解の重要な調節因子である.
研究 の 目的:
- [URE3]プリオン形成の構造的基礎を調査する.
- Ure2pがアミロイド繊維を形成し,拡散するメカニズムを解明する.
主な方法:
- Ure2p断片 (Ure2p1-65) の合成とポリメリゼーションの誘導.
- 電子顕微鏡とコンゴ赤色染色を用いた光線構造の分析.
- 合成断片の全長ネイティブUre2p.との共ポリメリゼーションを調査する.
- 形成されたフィラメントのプロテアゼ抵抗性を評価する.
主要な成果:
- 合成Ure2p1-65は,アミロイドフィラメント (40~45 Å 直径,ベータシートの60%以上) を形成した.
- Ure2p1-65による原生Ure2pのポリメリゼーションにより,プロテアゼ耐性フィラメント (180-220 Å 直径) が形成されます.
- これらのコフィラメントは,ネイティブUre2pのさらなるポリメリゼーションを,アミロイドの特徴であるより厚いフィラメントにシードした.
結論:
- Ure2pによる自己増殖性アミロイド形成は,[URE3]プリオンの感染性の性質を説明する.
- N末端の断片 (Ure2p1-65) は,Ure2pアミロイド形成の開始と拡散に不可欠です.
- アミロイドゲネシスは,酵母における非メンデルの遺伝のための分子メカニズムを提供します.
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