DNAの変動と超回転が起こります

J F Marko¹, E D Siggia

¹Laboratory for Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853-2501.

Science (New York, N.Y.)

|July 22, 1994

まとめ

DNAスーパーコイルは,DNAループの下から形成されます. エントロピーと弾性エネルギーはスーパーコイルの形状を決定し,再編成は遅い. 武力行使は,複雑なDNA拡張行動を明らかにする.

科学分野:

バイオフィジックス生物物理学
ポリマー物理学ポリマー物理学
分子生物学は分子生物学である.

背景:

DNA in vivoはしばしばループに編成されています.
これらのループは,しばしば部分的にアンダーウォンドされ,インターウォンドの螺旋型のスーパーコイルの形成につながります.
DNAスーパーコイルの形成と行動を支配する物理的原理を理解することは,DNAの組織と機能を理解するために極めて重要です.

研究の目的:

DNAスーパーコイルの半径とピッチを決定する物理的メカニズムを調査する.
スーパーコイル再構成のダイナミクスを分析し,特にDNAの滑り込み (反復) を用いて分析する.
適用された力の下で超巻きDNAの振る舞いを探求し,その拡張特性を観察する.

主な方法:

ポリマー統計力学原理の応用.
エントロピー力 (熱変動) と弾性エネルギーとの競争の分析.
理論的予測と実験・シミュレーションデータを比較する.
応用力によるDNAスーパーコイル拡張の理論モデリング.

主要な成果:

エントロピーと弾性エネルギーの間の競争は,実験とシミュレーションの発見と整合して,スーパーコイル半径とピッチをうまく予測します.
DNAのスライスリング (複製) は,スーパーコイルの再編成のための運動的に遅いプロセスとして識別されます.
適用された力による超巻きDNAの拡張は,インターウォンドとヘリケール状態の共存を含む予期せぬ現象を現します.

結論:

DNAスーパーコイルの物理的性質は,熱変動と弾性エネルギーのバランスによって支配されます.
スーパーコイルのダイナミクス,特にスライスリングによる再編成は遅い.
適用された力は,超巻きDNAの複雑な構造変化を誘導し,DNAの複雑な機械的性質を強調することができます.

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