在由 counterions 控制的 DNA 发针中电荷重组
Gail S Blaustein1, Brittany Demas, Frederick D Lewis
1Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, USA.
Journal of the American Chemical Society
|December 31, 2008
概括
在DNA发针中的电荷重组受 counterions 的影响. 离子与stilbene供体连接器结合的离子的存在显著改变了电荷重组速率,提供了一种控制这些过程的方法.
科学领域:
- 分子生物物理学 分子生物物理学
- 化学物理 化学物理
- DNA DNA 纳米技术 纳米技术
背景情况:
- 在DNA中电荷重组对于理解生物系统和合成结构中的电荷传输至关重要.
- 由于它们的定义结构,DNA针头为研究取决于距离的电子过程提供了一个独特的支架.
研究的目的:
- 为了研究不同长度的DNA针头中的缓慢电荷重组动力学.
- 阐明 counterions,特别是化物 (Cl-),在调节电荷重组速率中的作用.
- 通过离子操纵探索控制电荷重组的潜力.
主要方法:
- 实验研究了斯蒂尔供体 (Sd(+)) 和斯蒂尔受体 (Sa(-)) 连接器之间的电荷重组率.
- 采用不同长度的AT桥作为分子框架的DNA针头.
- 对距离依赖性的分析,揭示了归因于不同的道道的双倍指数形式.
主要成果:
- 观察到对电荷重组速率的双倍指数距离依赖.
- 与Sd(+) 连接器结合的Cl-对子离子的存在降低了正电荷能量,增加了重组障碍.
- 这导致在Cl-的存在下道化指数更大,这表明与其缺席相比,再组合的速度更慢.
结论:
- 难以理解的双指数依赖性是由两个道道解释的,它们的区别在于有或没有绑定的Cl-对应子.
- 相对子结合显著影响电荷重组动力学,提供速率调节的机制.
- 建议进行控制实验,用其他离子取代Cl-以进一步调整数量级的电荷重组率.
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