Reversible condensation of DNA using a redox-active surfactant
Reversible condensation of DNA using a redox-active surfactant
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DOI：
10.1021/la0700319
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发表时间：
2007-05-08
期刊：
影响因子：
3.9
通讯作者：
Abbott, Nicholas L.
中科院分区：
文献类型：
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作者：
Hays, Melissa E.;Jewell, Christopher M.;Abbott, Nicholas L.
我们报告了含有氧化还原活性表面活性剂（11-二茂铁基十一烷基）三甲基溴化铵（FTMA）的稀释 Lambda 噬菌体 DNA 水溶液的表征，作为 FTMA 氧化态的函数。 FTMA 经历可逆的单电子氧化，从在水溶液中形成胶束的还原态到在溶液中不自缔合的氧化态（包含二茂铁阳离子）。本研究试图验证 FTMA 可用于实现对溶液中 DNA-表面活性剂复合物构象的可逆控制的假设。尽管 DNA 在水溶液中采用延伸卷曲构象，但我们的测量表明，将还原的 FTMA (2-5 μM) 添加到 DNA 水溶液（核苷酸单位为 5 μM）中会导致溶液中延伸卷曲和致密小球的共存。在较高浓度的还原 FTMA（高达 30 μM）下，DNA 仅以致密小球形式存在。相比之下，氧化的FTMA对DNA的构象没有可测量的影响，使得DNA在高达75μM的氧化FTMA浓度下仍能保持延伸的卷曲状态。我们进一步证明，可以通过化学或电化学方式改变 FTMA 和 DNA 预形成复合物中 FTMA 的氧化态，从而实现对溶液中 DNA 构象的原位控制。这些结果为允许主动控制 DNA-表面活性剂相互作用的表面活性剂系统的设计提供了指导。
We report characterization of aqueous solutions of dilute Lambda phage DNA containing the redox-active surfactant (11-ferrocenylundecyl)trimethylammonium bromide (FTMA) as a function of the oxidation state of the FTMA. FTMA undergoes a reversible one-electron oxidation from a reduced state that forms micelles in aqueous solution to an oxidized state (containing the ferrocenium cation) that does not self-associate in solution. This investigation sought to test the hypothesis that FTMA can be used to achieve reversible control over the conformation of DNA-surfactant complexes in solution. Whereas DNA adopts extended coil conformations in aqueous solutions, our measurements revealed that addition of reduced FTMA (2-5 mu M) to aqueous solutions of DNA (5 mu M in nucleotide units) resulted in coexistence of extended coils and compact globules in solution. At higher concentrations of reduced FTMA (up to 30 mu M), the DNA was present as compact globules only. In contrast, oxidized FTMA had no measurable effect on the conformation of DNA, allowing DNA to maintain an extended coil state up to a concentration of 75 mu M oxidized FTMA. We further demonstrate that it is possible to chemically or electrochemically transform the oxidation state of FTMA in preformed complexes of FTMA and DNA, thus achieving in situ control over the conformations of the DNA in solution. These results provide guidance for the design of surfactant systems that permit active control of DNA-surfactant interactions.