SCFCdc4ダイマーの表面的な指向は,基板のユビキチネーションのための複数の幾何学に対応します
Xiaojing Tang1, Stephen Orlicky, Zhenyuan Lin
1Centre for Systems Biology, Samuel Lunenfeld Research Institute, Toronto, Ontario, Canada M5G 1X5.
Cell
|June 19, 2007
まとめ
SCFユビキチンリガゼのDドメインはジマーを形成し,基板のユビキチン化を強化する. この二重化は,基板とユビキチン鎖における多様なライシン幾何学に対応することによって,触媒効率を最適化します.
科学分野:
- * 分子・細胞生物学
- * バイオケミストリー
- * 構造生物学について
背景:
- *SCFユビキチンリガゼは,F-ボックスタンパク質アダプタを通して基板の分解を媒介する.
- * Cdc4やβ-TrCPのようなWD40リピートFボックスタンパク質は,機能に不可欠なDドメインを保存している.
- * SCF複合体におけるDドメインの二次元構造と触媒的影響は,まだ完全に理解されていません.
研究 の 目的:
- *SCFユビキチンリガゼ複合体におけるDドメイン媒介ダイメリゼーションの構造的・機能的影響を調査する.
- * 基板認識とユビキチン結合効率におけるSCF二分化の役割を明らかにする.
- * 二次元のSCF複合体内の主要な触媒成分の空間的配置をモデル化する.
主な方法:
- * 酵母Cdc4とヒトβ-TrCPのDドメインプロトメアの構造分析.
- * バイオケミカルアッセイで,SCF ((Cdc4) の活動に対するDドメインの障害がSic1.1への影響を評価する.
- *小角X線散射 (SAXS) 測定により,ホロSCF ((Cdc4)) 複合構造をモデル化しました.
主要な成果:
- *酵母Cdc4とヒトβ-TrCP Dドメインは,超ヘリカルな同型二重体を形成する.
- * Dドメインの破壊は,Sic1.1.のような基板に対するSCF ((Cdc4) の活動を損なう.
- *SCF (((Cdc4) ダイメリゼーションは,基質の親和性を大きく変化させることなく,ユビキチン結合を強化します.
- *SAXSモデリングは,二次元ホロ-SCF ((Cdc4) 複合体の表面構成を示しています.
結論:
- * Dドメイン媒介型二酸化は,SCFユビキチンリガゼの触媒効率に不可欠である.
- * 立体構造は,基板とE2結合部位を配置して,多様な幾何学に対応します.
- *この空間的配置は,効率的なユビキチン移転と基板の分解を容易にする.
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