ヘクサアメリカンヘリケーズDnaBは,転位時に非平面的形状を採用する
Ornchuma Itsathitphaisarn1, Richard A Wing, William K Eliason
1Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
Cell
|October 2, 2012
まとめ
DNA複製に不可欠な細菌のDNAヘリケーズDnaBは,単一鎖DNAの周りに螺旋階段構造を形成する. この構造は,DNAの解き放たれるための独特な手と手との転位メカニズムを明らかにしています.
科学分野:
- バイオケミストリー バイオケミストリー
- 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
背景:
- DNAポリメラーゼは合成のために単一鎖DNA (ssDNA) テンプレートを必要とします.
- 細菌のDNA複製は,DnaBのような複製性DNAヘリケーズに依存し,重複DNAを解き放つ.
- DnaBはNTPの水解を5'から3'の方向転位に結びつけます.
研究 の 目的:
- DnaBの転移メカニズムの構造的基盤を明らかにする.
- 超家族IVヘリケスの解き放たれる過程についての洞察を提供するため.
- DnaBメカニズムを,他の既知のヘリカーゼスーパーファミリーと比較するために.
主な方法:
- DnaBヘクサマーのX線結晶学.
- GDP-AlF(4) とssDNA.との複合形成である.
- 四角構造の構造分析とssDNAの調整.
主要な成果:
- 結晶構造は,DnaBがA型ssDNAの周りに閉じた螺旋の階段を形成していることを示しています.
- それぞれのDnaB C端末ドメインは,ssDNAの2つの核酸を調整する.
- 構造は,他のヘリケーズ超家族とは異なる転位機構を示唆しています.
結論:
- DnaBは,ssDNAに沿ってトランスロケーションを行うために,ハンド・オーバー・ハンドメカニズムを使用しています.
- 連続的なNTP水解は,連続的なサブユニット移動を駆動し,DNAを解き放つ.
- このメカニズムは,スーパーファミリーIVヘリケースのDNA解き放たれに関する新しい理解を提供します.
関連する概念動画
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The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
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