デュプレックスDNAオリゴーマーにおける酸化的に損傷した核塩基:チミン-チミンミズペアの反応
Joshy Joseph1, Gary B Schuster
1School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Journal of the American Chemical Society
|September 15, 2009
まとめ
DNA内のチミン-チミンミスペアは,ラジカルカチオンの動きを遮断し,好ましい反応部位になる. thymine を uracil に置き換えるのは,その反応部位としての役割を強調し,輸送を充電するための障壁となる.
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.
- フォトケミストリー フォトケミストリー
背景:
- タイミン-タイミン (TT) の不一致は,DNA内の長距離の根幹カチオン移動を阻害することが知られている.
- これらの不一致は,二重複 DNA オリゴマーの高度反応性サイトを表しています.
研究 の 目的:
- 基幹カチオン移動とDNAオリゴマーの反応性におけるTTミスペアの役割を調査する.
- 光誘発酸化後のDNA鎖の分裂に対するTT不一致の影響を解明する.
主な方法:
- 繰り返し TT ステップを繰り返す A/T 塩基対のみで構成される DNA オリゴメアとアントラキノン 光敏感剤の合成.
- 一電子酸化を誘発するUV照射と,その後DNA鎖の分裂パターンの分析.
- 反応性および輸送効果を評価するために,ウラシルで置き換えることを含む,TTミスペアのサイト固有の修正.
主要な成果:
- DNAオリゴメアの光酸化により,ラジカルカチオンが形成され,TTステップで優先反応と鎖分裂が起こります.
- リモートGGステップの導入により,TTステップでの反応性が著しく低下し,割れは主にGGステップで発生しました.
- オリゴーマー内のTT不配合は,不配合部位と以前のTTステップで鎖裂けを引き起こし,遠隔のGGステップで反応をブロックしました.
- ミスペアのチミンをウラシルに置き換えることで,ミスペアが反応部位であり,ラジカル・カチオン・ホッピングの障壁であることを確認した.
結論:
- ティミン-ティミンミスマップは,DNAの長距離の急性カチオン移動に重大な障壁として作用します.
- これらの不一致は,急性カチオン反応と,その後のDNA鎖の分裂のための好ましい場所です.
- 観測された効果は,チミン-チミン不一致の振動ベースペア構造と潜在的に関連している.
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