人間のリボヌクレアースPホロ酵素の冷凍-EM構造

Jian Wu¹, Shuangshuang Niu², Ming Tan³

¹Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.

Cell

|November 21, 2018

まとめ

人間の核RNase Pは,tRNAの成熟に不可欠なリボ酵素であり,基板結合のために複雑なタンパク質-RNA構造を使用します. tRNA結合はリボ酵素を活性化する

科学分野:

生物化学
分子生物学
構造生物学

背景:

リボヌクレアース (RNase) Pは,前駆体tRNAを処理する重要な酵素である.
RNase Pは,触媒RNAとタンパク質からなるリボ核タンパク質複合体である.
人間のRNase Pの構造と機能を理解することは,tRNAの生体生成に極めて重要です.

研究の目的:

人間の核RNase P機能の構造的基礎を解明する.
人間のRNase PによるtRNA認識と結合のメカニズムを調査する.
バクテリアとより高い生物の間のRNase Pの進化的多様性を探求する.

主な方法:

高解像度構造を決定するために,冷凍電子顕微鏡 (cryo-EM) が使用されました.
ヒト核RNase Pの構造は,単離 (アポ状態) とtRNAとの複合体で得られた.
基板結合時の構造変化を特定するために,比較構造分析が行われました.

主要な成果:

人間の核RNase P複合体は10のタンパク質と1つの触媒RNAで構成され,安定したクランプを形成します.
タンパク質-RNAとRNA-RNAの相互作用を含む二重アンカーメカニズムがtRNA認識を媒介する.
tRNA結合は,リボ酵素を活性化して,触媒中心の局所的な形状変化を誘導する.

結論:

人間のRNase Pは,tRNAの結合と触媒を容易にするために,高度なタンパク質基板を使用します.
RNase Pの進化は,バクテリアにおけるRNA中心のメカニズムから,ヒトにおけるタンパク質主導の調節への移行を伴う.
これらの発見は,この重要なリボ酵素の構造的動態と進化の軌道を洞察します.

キーワード:

RNase P についてクリオ・エムリボジーム

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