ポリメラーゼ活性部位にあるDNAとTaqポリメラーゼの構造
1Department of Molecular Biophysics, Yale University, New Haven, Connecticut 06520-811, USA.
Nature
|July 18, 1996
まとめ
研究者らは,活性部位のDNAに結合するTaqポリメラーゼの構造を決定した. これは,この酵素が,以前のKlenowの断片構造と異なる,ぼんやりしたDNAをどのように結合するかを明らかにします.
科学分野:
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
- 分子生物学は分子生物学である.
背景:
- Taqポリメラーゼは,ポリメラーゼと5'核酸ドメインを持つE. coli DNAポリメラーゼI (Pol I) と同質性を共有しています.
- Taqポリメラーゼの3'-5'エクソヌクレアースドメインは構造的に変化しており,Pol IのKlenow断片と比較して編集機能が欠けている.
- 以前の構造研究では,ポリメラーゼ活性部位で二重複DNAを持つTaqポリメラーゼの複合体が欠けていた.
研究 の 目的:
- ポリメラーゼの活性部位のぼんやりしたデュプレックスDNAに結合するTaqポリメラーゼの共結晶構造を解明する.
- DNA結合とTaqポリメラーゼによる活性部位での認識の構造的基礎を理解する.
主な方法:
- Taqポリメラーゼの共結晶学で,ぼんやりしたデュプレックスDNA.
- 3次元構造を決定するX線 difraktion分析.
主要な成果:
- 同結晶構造は,Taqポリメラーゼが活性部位裂け目内の鈍い末端のデュプレックスDNAに結合していることを示しています.
- DNAは著しく曲げられず,B-DNAとA-DNAの間の中間構造形態を採用しています.
- 広い小さな溝は,DNA末端とタンパク質の相互作用を容易にし,結合部位はエクソヌクレアゼ部位と重複する.
結論:
- 決定された構造は,活性部位におけるTaqポリメラーゼによるDNA結合のメカニズムについての洞察を提供します.
- 構造的な違いは,Taqポリメラーゼにおける3'-5'エクソヌクレアースの活性がないことを説明する.
- この研究は,熱安定酵素におけるDNAポリメラーゼ-DNA相互作用の理解を前進させる.
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