Dasgupta Antara, Das Prasanta Kumar, Dias Rita S, Miguel Maria G, Lindman Björn, Jadhav Vaibhav M, Gnanamani Muthaiah, Maiti Souvik
Department of Biological Chemistry, Centre for Advanced Materials, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
J Phys Chem B. 2007 Jul 26;111(29):8502-8. doi: 10.1021/jp068571m. Epub 2007 Jun 6.
The interaction behavior of DNA with different types of hydroxylated cationic surfactants has been studied. Attention was directed to how the introduction of hydroxyl substituents at the headgroup of the cationic surfactants affects the compaction of DNA. The DNA-cationic surfactant interaction was investigated at different charge ratios by several methods like UV melting, ethidium bromide exclusion, and gel electrophoresis. Studies show that there is a discrete transition in the DNA chain from extended coils (free chain) to a compact form and that this transition does not depend substantially on the architecture of the headgroup. However, the accessibility of DNA to ethidium bromide is preserved to a significantly larger extent for the more hydrophilic surfactants. This was discussed in terms of surfactant packing. Observations are interpreted to reflect that the surfactants with more substituents have a larger headgroup and therefore form smaller micellar aggregates; these higher curvature aggregates lead to a less efficient, "patch-like" coverage of DNA. The more hydrophilic surfactants also presented a significantly lower cytotoxicity, which is important for biotechnological applications.
研究了DNA与不同类型羟基化阳离子表面活性剂的相互作用行为。重点关注阳离子表面活性剂头基引入羟基取代基如何影响DNA的压缩。通过紫外熔解、溴化乙锭排斥和凝胶电泳等几种方法，在不同电荷比下研究了DNA与阳离子表面活性剂的相互作用。研究表明，DNA链从伸展的线圈（自由链）到紧密形式存在离散转变，并且这种转变基本上不依赖于头基的结构。然而，对于亲水性更强的表面活性剂，DNA对溴化乙锭的可及性在更大程度上得以保留。这从表面活性剂堆积的角度进行了讨论。观察结果被解释为反映出具有更多取代基的表面活性剂具有更大的头基，因此形成更小的胶束聚集体；这些具有更高曲率的聚集体导致对DNA的覆盖效率较低，呈“斑块状”。亲水性更强的表面活性剂还表现出显著更低的细胞毒性，这对于生物技术应用很重要。
