RNAスキャフォールド上の活性化されたGTPaseの動きは,共同翻訳タンパク質をターゲットに駆動する
Kuang Shen1, Sinan Arslan, David Akopian
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
Nature
|December 14, 2012
まとめ
信号認識粒子 (SRP) RNAは,分子支架として作用し,精密なタンパク質標的化のためにSRP-SRP受容体複合体の動きを誘導します. このRNAベースのメカニズムは,タンパク質の膜への正確な配送を保証します.
科学分野:
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
- 細胞生物学 細胞生物学
背景:
- タンパク質の局所化は,信号認識粒子 (SRP) 経路によって媒介される細胞機能にとって極めて重要です.
- リボ核タンパク質複合体であるSRPは,タンパク質をエンドプラズマ網膜またはプラズマ膜に標的にします.
- このメカニズムにおける長方形のSRPRNAの正確な役割は不明である.
研究 の 目的:
- タンパク質標的化経路におけるSRPRNAの機能的役割を明らかにする.
- SRP RNA上のSRP-SRP受容体複合体のダイナミクスを調査する.
- タンパク質転位開始の規制を理解するために.
主な方法:
- 単分子光顕微鏡を用いて,SRP-SRP受容体複合体の動きを追跡した.
- 研究はEscherichia coliシステムを使用して行われました.
- リボソームとSecYEGトランスロコンの規制的な役割が検討されました.
主要な成果:
- SRP-SRP受容体GTPase複合体は,SRP RNAに沿って100 Å以上移動し,テトラロップ端からディスタル端まで移動する.
- GTPの水解は,SRP RNAのディスタル端で起こります.
- リボソームは,この動きをネガティブに制御し,SecYEGトランスロコンは,後でそれをポジティブに制御する.
結論:
- SRP RNAはダイナミックな分子構造として機能し,タンパク質を標的とする時の空間的および時間的精度を調整します.
- このRNA媒介メカニズムは,リボソームにおけるターゲティングと転位機構の交換を容易にする.
- この発見は,リボヌクレオプロテイン複合体のダイナミクスを調節する際に,RNAスキャフォルドのより広範な原理を示唆している.
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