ヒトヒストンメチルトランスフェラーゼSET7/9の構造と触媒機構
Bing Xiao1, Chun Jing, Jonathan R Wilson
1Structural Biology Group, National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
Nature
|January 24, 2003
まとめ
人間のSET7/9は,他のSETタンパク質とは異なり,ユニークなモノメチラーゼです. その結晶構造は,ヒストンの標的とコファクターが結合する方法を明らかにし,メチル化特異性と反応機構を説明します.
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.
- エピジェネティクス エピジェネティクス
背景:
- アセチル化,リン酸化,甲基化を含むヒストンの翻訳後の改変は,クロマチンの構造と機能を調節する.
- ヒストンのメチル化は主にSET (Su(var) 3-9,Enhancer-of-zeste,Trithorax) ドメイン酵素によって触媒され,最も知られている酵素は特定のライシン残基をメチル化する.
研究 の 目的:
- ヒトSET7/9.9によるヒストンのメチル化特異性の構造的基礎を解明する.
- SET7/9媒介メチル化とコファクターの相互作用の仕組みを理解する.
- SET7/9をモノメチラーゼとして特徴付けます.
主な方法:
- 人間のSET7/9,ヒストンペプチド,およびコファクターS-アデノシル-l-メチオニン (AdoMet) を含む三元複合体の高解像度結晶構造決定.
- 酵素活性と基板特異性を確認するための溶液試験.
- 酵素活性部位内の重要な相互作用とチャネルを特定するための構造分析.
主要な成果:
- 結晶構造は,ヒストンペプチド基板とAdoMetコファクターがSET7/9.9の対面面に結合することを明らかにしています.
- 酵素内の狭いチャネルは,ターゲットライシンサイドチェーンが活性部位とコファクターへのアクセスを促進します.
- SET7/9は独占的にモノメチラーゼであることを確認し,他のSETタンパク質と区別しました.
- この構造は,SET7/9のヒストン標的に対する特異性に対する分子基盤の洞察を提供します.
結論:
- SET7/9ヒストンペプチド-アドメット複合体の構造は,基質へのアクセスのためのユニークな結合モードとチャネルを明らかにします.
- SET7/9は特定のモノメチラーゼとして機能し,その構造的特徴が基質認識と反応機構を説明します.
- この発見は,SETドメインのタンパク質が表遺伝子調節における多様な役割を理解するのに寄与する.
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