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DNA电荷传输:通过堆叠的域跳跃通过构造性门
Melanie A O'Neill1, Jacqueline K Barton
1Contribution from the Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Journal of the American Chemical Society
|September 16, 2004
概括
在DNA中的基体运动显著影响长距离的电荷传输 (CT). 取决于温度的DNA基底波动使扩展CT成为可能,揭示了一个复杂的,非线性距离依赖,这对于理解DNA动态至关重要.
科学领域:
- 生物物理学的生物物理.
- 分子生物学分子生物学
- 物理化学 物理化学
背景情况:
- 了解DNA介导的电荷传输 (CT) 需要纳入基础运动的作用.
- 现有的模型往往无法解释CT在DNA中的实验观测.
- CT的温度依赖性及其距离关系尚未完全理解.
研究的目的:
- 实验性地研究DNA基底运动在电荷传输 (CT) 中的作用.
- 为了检查CT产量和DNA中距离关系的温度依赖性.
- 为了阐明DNA介导的电荷传输机制.
主要方法:
- 构建了具有腺因桥梁 (Ap(A) nG) 和混合序列的35默尔DNA组件.
- 研究了光激发的2-aminopurine (Ap) 和关氨酸 (G) 进行CT.
- 通过光火和HPLC对改性瓜 ((CP) G) 的分析监测CT.
主要成果:
- 双重DNA中的CT产量随着温度低于点 (约. 60°C) 的温度.
- 在更高的温度下增强的DNA基底波动将CT距离延长至34 Å.
- CT距离依赖性显示了一个振荡元件 (4-5个基数对),不能用简单的模型来解释.
结论:
- 通过DNA介导的CT不仅仅取决于距离,而且与DNA的动态结构密切相关.
- CT发生在短暂的,合良好的DNA基体构造 ("CT活性域") 中,通过基体运动访问.
- 在堆叠的域之间采用'形态封闭的跳跃'模型来解释观察到的CT行为.
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