DNA合成は,ヘリカーゼによるDNA解を加速させる原動力を供給する
Natalie M Stano1, Yong-Joo Jeong, Ilker Donmez
1Department of Biochemistry, UMDNJ-Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, New Jersey 08854, USA.
Nature
|May 20, 2005
まとめ
バクテリオファージT7ヘリケーゼは,二重複DNAをゆっくりと解き放ちます. T7DNAポリメラーゼと組み合わせると,ヘリカーゼ解速度が大幅に増加し,単一鎖DNAの解速度に匹敵する.
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
- ウイルス学 ウイルス学 ウイルス学
背景:
- ヘリカーゼは,核酸鎖の転位と解き放出のために核酸5'-三リン酸 (NTP) を水解する分子モーターである.
- バクテリオファージT7ヘリケーゼは,単一鎖DNA (ssDNA) では130塩基/秒で動くが,二重DNAでは10倍遅い.
研究 の 目的:
- T7ヘリケースの二重DNA解速度を高めるT7DNAポリメラーゼの役割を調査する.
- DNAポリメラーゼの活性がヘリコース転位速度に影響するメカニズムを理解する.
主な方法:
- T7ヘリカーゼとT7DNAポリメラーゼの活性 in vitroの特徴.
- DNAポリメラーゼの存在と不在でDNA解き放つ速度を測定するアッセイ.
- DNA合成速度に対するヘリカーゼ刺激の依存性の分析.
主要な成果:
- T7DNAポリメラーゼは,T7ヘリケースの解離率を114塩基対/秒に大幅に増加させます.
- ヘリカーゼ刺激は,特定のタンパク質-タンパク質相互作用ではなく,DNA合成速度に依存しています.
- 効率的な二重DNA合成には,ヘリケーズとポリメラーゼの両方の協調した作用が必要です.
結論:
- T7ヘリケーゼとT7DNAポリメラーゼの結合作用により,迅速な二重複DNA解離と合成が可能になります.
- DNAポリメラーゼの活動は,ssDNAを素早く捕まえて,重複DNAを通してヘリコースの転位を活発に駆動します.
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03:01The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
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...
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...