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Design and Synthesis of a Reconfigurable DNA Accordion Rack
Published on: August 15, 2018
DNA兴奋状态动态:在一系列核酸中,超快的内部转换和振动冷却
J M Pecourt1, J Peon, B Kohler
1Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA.
Journal of the American Chemical Society
|October 18, 2001
概括
DNA 基很快将有害的紫外线能量以热的形式消散,从而防止光损伤. 这种通过 Femtosecond 光谱学研究的快速冷却机制,对于 DNA 稳定性和潜在的早期生命进化至关重要.
科学领域:
- 摄影化学的使用.
- 分子光谱学 分子光谱学
- 生物物理学的生物物理.
背景情况:
- DNA光损伤对遗传完整性构成重大威胁.
- 了解DNA核基的光物理路径对于解释它们对紫外线辐射的抗性至关重要.
- 之前的研究缺乏直接观察室温激发状态动态.
研究的目的:
- 为了研究DNA核酸的激发单片状态动力学,使用femtosecond暂时吸收光谱学.
- 为了确定各种核酸的兴奋状态寿命和能量消散途径.
- 阐明这些动态在DNA光保护中的作用.
主要方法:
- 五秒短暂吸收光谱使用263nm紫外线脉冲和连续探针脉冲.
- 在不同的pH值下在水溶液中研究核酸 (腺素,瓜诺素,氨酸,氨酸).
- 在270-700nm范围内分析吸收带和衰变动力学.
主要成果:
- 检测到对质子化瓜诺辛和其他核酸的兴奋状态吸收带.
- 确定亚皮秒激发状态寿命的腺素 (290 fs),瓜诺素 (460 fs),丁 (720 fs) 和硫胺素 (540 fs).
- 通过溶解物-溶剂相互作用观察到快速的内部转换到基本状态和随后的振动冷却,氨酸的时间常数为2ps.
结论:
- 通过快速的内部转换,DNA基有效地将紫外线能量作为热消散,防止光损伤.
- 观察到的兴奋状态动态和振动冷却机制是DNA光保护的基础.
- 这种快速的能量消耗可能在地球生命的进化中发挥了关键作用.
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