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Rho転写ターミネーターの構造:mRNA認識とヘリカーゼ負荷のメカニズム

Emmanuel Skordalakes¹, James M Berger

¹Department of Molecular and Cell Biology, University of California, Berkeley, 239 Hildebrand Hall, #3206, Berkeley, CA 94720, USA.

|July 16, 2003

まとめ

転写の終結に不可欠なヘリコースである細菌のRho因子は,ユニークな"ロックウォッシャー"ヘクサアメリカンリングを形成します. このオープンな構造は,標的mRNAへの結合を促進し,核酸相互作用のメカニズムを明らかにします.

科学分野:

分子生物学は分子生物学である.
構造生物学構造生物学とは
バイオケミストリーバイオケミストリー

背景:

バクテリアの転写終結は,重要なRNA/DNAヘリカーゼであるRho因子に依存しています.
Rho因子の構造と機能を理解することは,遺伝子調節を解読する鍵です.

研究の目的:

核酸複合体のRho因子の高解像度構造を決定するために,核酸模倣.
Rho因子のmRNA結合および転位機構の構造的基礎を解明する.

主な方法:

X線結晶学を用いて,Rho複合体の2つの構造を決定した.
構造は,自由状態と核酸結合状態の両方で3.0 Åの解像度で解像しました.

主要な成果:

Rho因子は,内側に向けられた2つの異なるRNA結合部位を持つヘクサアメリカンリングを形成する.
ヘクサアメリカンリングは,閉ざされたリングではなく,オープンで"ロックウォッシャー"の形状を採用しています.
開口は幅約12 Åで,単一鎖RNAを収納しています.

結論:

オープンリングの構造は,mRNAにロードされるためのコンフォームを示唆しています.
この構造的洞察は,環状ヘリカーゼが核酸を結合する方法のモデルを提供します.
この発見は,細菌の転写調節に関する理解を深める.

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