Krishnaswamy Rema, Raghunathan V A, Sood A K
Raman Research Institute, Bangalore 560 080, India.
Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Mar;69(3 Pt 1):031905. doi: 10.1103/PhysRevE.69.031905. Epub 2004 Mar 17.
Complexes of double-stranded DNA with the cationic surfactant cetyltrimethylammonium bromide have been studied using small angle x-ray diffraction at varying concentrations of DNA and the cosurfactant hexanol. At low DNA concentrations, an intercalated hexagonal (H(c)(I))-->lamellar (L(c)(alpha))-->inverted hexagonal (H(c)(II)) transformation is found on increasing hexanol content. The H(c)(II) structure is converted into L(c)(alpha) on adding more DNA. Further increase in hexanol content leads to a phase separation in the surfactant solution, and a reentrant L(c)(alpha)-->H(c)(II)-->L(c)(alpha) transition is observed as DNA concentration is increased. Such structural transformations of DNA-surfactant complexes, driven by DNA concentration, have not been reported until now.
使用小角X射线衍射技术，在不同的DNA浓度和共表面活性剂己醇浓度下，对双链DNA与阳离子表面活性剂十六烷基三甲基溴化铵形成的复合物进行了研究。在低DNA浓度下，随着己醇含量的增加，发现了一种插层六方（H(c)(I)）→层状（L(c)(α)）→反相六方（H(c)(II)）转变。添加更多DNA时，H(c)(II)结构会转变为L(c)(α)。进一步增加己醇含量会导致表面活性剂溶液发生相分离，并且随着DNA浓度的增加，会观察到一个折返的L(c)(α)→H(c)(II)→L(c)(α)转变。直到现在，由DNA浓度驱动的DNA-表面活性剂复合物的这种结构转变尚未见报道。
