DNAにおけるグアニン基のカチオンの水分化のメカニズム的な側面
Yekaterina Rokhlenko1, Jean Cadet, Nicholas E Geacintov
1Chemistry Department, New York University , 31 Washington Place, New York, New York 10003-5180, United States.
Journal of the American Chemical Society
|April 3, 2014
まとめ
DNAの二次構造は,グアニン基幹のカチオン水分化に影響する. 二重鎖のDNAは,単一鎖のDNAとは異なり,陽子共有メカニズムによって8オキシ-7,8ジヒドログアニン (8-オキシG) の形成を促進する.
科学分野:
- バイオ物理化学 バイオ物理化学
- 分子生物学は分子生物学である.
- スペクトロスコーピーは,スペクトロスコーピーを用います.
背景:
- グアニンラジカルカチオン (G(•+)) は,DNA損傷における重要な中間物質である.
- 彼らの水分補給メカニズムを理解することは,DNA修復と安定性研究にとって極めて重要です.
研究 の 目的:
- 二重鎖および単一鎖DNAにおけるグアニン基幹カチオン水分化のメカニズム的側面を調査する.
- 8-オクソ-7,8-ジヒドログアニン (8-オクソG) の形成におけるDNA二次構造の役割を明らかにする.
主な方法:
- 直接時間解像度スペクトルモニタリング.
- S2O8(2-) 光分解から SO4((•-) 基離子によるGの生成.
- 308 nmのレーザーパルスです.
主要な成果:
- 中性DNAでは,SO4の分解後に312nmで λmax を有する中性グアニン基 (G(-H)(•)) が優勢である.
- G (((-H) (((•) 崩壊運動は,DNA構造の間で有意に異なっています:二相性では二重鎖DNA (msとs成分) で,単一鎖DNA (s成分) では単相性です.
- 二重鎖DNAは,8oxoGの ~7倍以上の出産を示しており, ms 腐敗成分と相関しています.
結論:
- 二重鎖DNAの提案されたメカニズムは,G(-H)(•) が[G(•+):C]塩基対でサイトシン (C) と陽子を共有し,G(•+) の水分化と8oxoGの形成を促進する.
- 単一鎖DNAでは,陽子脱出は水分化と競合し,8-oxoGの産量を減少させます.
- DNAの二次構造は,グアニンの酸化と,その後の損傷産物形成を決定的に調節する.
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