転写と翻訳の結合の構造的基礎
Chengyuan Wang1, Vadim Molodtsov1, Emre Firlar2
1Waksman Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA.
Science (New York, N.Y.)
|August 22, 2020
まとめ
バクテリアの転写-翻訳結合にはRNAポリメラーゼ (RNAP) とリボソームが含まれます. NusGとNusaAが特定の複合体を通してこのプロセスを促進する方法を明らかにしています
科学分野:
- 分子生物学
- 微生物学
- 構造生物学
背景:
- 転写と翻訳はバクテリアで結合し,RNAポリメラーゼ (RNAP) とリボソームがmRNA合成とタンパク質合成を調整する.
- 転写因子であるNusGとNusAは,この結合プロセスを調節することが知られている.
- トランスクリプション・トランスレーション・コンプレックス (TTC) 内のNusGブリッジングとNusA結合の正確なメカニズムは不明のままである.
研究 の 目的:
- エシェリキア・コロイにおける転写-翻訳結合の構造的基礎を解明する.
- 複写因子 NusG と NusA が RNAP とリボソームと結合した過程でどのように相互作用するかを決定する.
- mRNAスペーサーの長さに基づくトランスクリプション・トランスレーション・コンプレックス (TTC) の異なる状態を特徴付ける.
主な方法:
- クリオ電子顕微鏡 (cryo-EM) を使用して,Escherichia coli* 転写翻訳複合体 (TTC) の高解像度構造を決定した.
- RNAPとリボソーム間の異なる長さのメッセンジャーRNA (mRNA) の複合体を分析した.
- 構造分析は,RNAP,リボソーム,NusG,NusAの結合インターフェースと構成状態に焦点を当てた.
主要な成果:
- 2つの異なるTTC状態がmRNAスペーサーの長さに基づいて識別された:TTC-A (短いスペーサー) とTTC-B (より長いスペーサー).
- TTC-A構造は,NusGブリッジとNusA結合と相容れない構造を示した.
- TTC-B構造は,NusGのブリッジングとNusAの結合を可能にする新しい構成を明らかにし,それらの相互作用部位を詳細に示した.
結論:
- この研究では,バクテリアの転写-翻訳複合体 (TTC) の異なる構造状態がmRNAスペーサー長さに依存することを明らかにした.
- 新しい状態であるTTC-Bは,NusGとNusAの結合を促進し,NusGとNusAに依存する転写-翻訳結合を媒介する.
- これらの発見は,細菌における遺伝子発現の調整を制御する分子機構に関する重要な洞察を提供します.
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