Entrapment and condensation of DNA in neutral reverse micelles

被引:38
作者
Budker, VG
Slattum, PM
Monahan, SD
Wolff, JA
机构
[1] Univ Wisconsin, Waisman Ctr, Dept Pediat & Med Genet, Sch Med, Madison, WI 53705 USA
[2] Mirus Corp, Madison, WI 53719 USA
关键词
D O I
10.1016/S0006-3495(02)75508-2
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
DNA condensation and compaction is induced by a variety of condensing agents such as polycations. The present study analyzed the structure of plasmid DNA (DNA) in the small inner space of reverse micelles formed from nonionic surfactants (isotropic phase). Spectroscopic studies indicated that DNA was dissolved in an organic solvent in the presence of a neutral detergent. Fluorescent quenching of ethidium bromide and of rhodamine covalently attached to DNA suggested that the DNA within neutral, reverse micelles was condensed. Circular dichroism indicated that the DNA structure was C form (member of B family) and not the dehydrated A form. Concordantly, NMR experiments indicated that the reverse micelles contained a pool of free water, even at a ratio of water to surfactant (Wo) of 3.75. Electron microscopic analysis also indicated that the DNA was in a ring-like structure, probably toroids. Atomic force microscopic images also revealed small, compact particles after the condensed DNA structures were preserved using an innovative cross-linking strategy. In the lamellar phase, the DNA was configured in long strands that were 20 nm in diameter. Interestingly, such DNA structures, reminiscent of "nanowires," have apparently not been previously observed.
引用
收藏
页码:1570 / 1579
页数:10
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