在循环DNA小双复合体中诱导紫外线的质子-合电子转移
Yuyuan Zhang1, Xi-Bo Li2, Aaron M Fleming2
1Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States.
Journal of the American Chemical Society
|May 21, 2016
概括
紫外线会激发DNA微复合体, 触发电子和质子的转移. 一种经过修改的关氨酸残留物破坏了这一过程,显示了堆叠的基对如何控制DNA激发状态衰变途径.
科学领域:
- 摄影化学
- 分子生物物理学
- DNA动力学
背景情况:
- 了解DNA激发状态的动态对于光化学和光生物学来说至关重要.
- 之前对较长的DNA复合体的研究表明,复杂的衰变途径涉及电子和质子转移.
- 研究最小的DNA结构可以阐明基本的光物理过程.
研究的目的:
- 为了研究最小DNA双重体的兴奋状态动态.
- 阐明基质堆叠和配对在DNA激发状态衰变中的作用.
- 要确定简单的DNA结构是否可以在更长的序列中模拟衰变通道.
主要方法:
- 用时间分辨率的红外光谱来监测超快的过程.
- 合成和研究了两个循环DNA微复合体,每一个都有两个基对.
- 引入了修改后的关氨酸 (8-oxo-7,8-dihydroguanine),以探测破坏基层堆叠的影响.
主要成果:
- 在G·C微双体中,UV激发引发的线条内电子转移,随后是线条内质子转移.
- 这种转移所带来的兴奋状态在几十个皮秒内消失.
- 用8-oxo-7,8-dihydroguanine替换关氨酸消除了这种激发状态,这表明叠的重要性.
结论:
- 一个双基对DNA小双有效地模拟了链内和链间衰变通道的相互作用.
- 在较长的DNA复合体中,激发状态可能会局部化在两个相邻的基对上.
- 基质堆叠在DNA激发状态动态和衰变途径中起着至关重要的作用.
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