ヴァルクド衛星リボ酵素における基板ヘリックス再構成と割れ目ループ活性化の構造的基礎

Saurja DasGupta¹, Nikolai B Suslov¹, Joseph A Piccirilli¹

¹Department of Chemistry, and ‡Department of Biochemistry and Molecular Biology, The University of Chicago , Chicago, Illinois 60637, United States.

Journal of the American Chemical Society

|June 20, 2017

まとめ

ヴァルクード衛星リボジーム

科学分野:

生化学と分子生物学
RNA触媒
構造生物学

背景:

Varkud衛星 (VS) リボ酵素は,サイト特有のRNA分裂と結合を行う触媒RNA分子である.
基板の認識と活性化には,キスループの相互作用によって媒介される重要な"シフトした"形状が含まれます.
このメカニズムを理解することは RNAベースの触媒解読の鍵です

研究の目的:

Varkud 衛星リボ酵素における基板活性化の構造的基礎を解明する.
リボ酵素基質複合体の触媒的に活性な構成を視覚化する.
RNAの折りたたみと触媒の信頼性についての洞察を提供するためです

主な方法:

3.3 Åの解像度のX線結晶学を用いて,その基質を含む完全なVSリボ酵素の構造を決定した.
孤立した基板の核磁気共鳴 (NMR) 構造と比較する.

主要な成果:

結晶構造は,活性状態の完全なリボ酵素を明らかにし,基板は,触媒領域に結合した重要な"シフトした"形状である.
構造は,不活性状態から活性状態への基板改造の詳細な物理的記述を提供します.
分裂ループの活性化には,三次相互作用が関与している.

結論:

決定された構造は,VSリボ酵素における基板活性化と再構成のメカニズム的理解を提供します.
発見は,触媒効率のための特定の三次相互作用の重要性を強調します.
ヘアピンリボエンザイムとの類似性は,RNAの折りたたみ精度とリボエンザイム活性を高めるための保存された戦略を示唆する.

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