Nanostructures of Complexes Formed by Calf Thymus DNA Interacting with Cationic Surfactants

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• 作者：Shuiqin Zhou ; Dehai Liang ; Christian Burger ; Fengji Yeh ; and Benjamin Chu
• 刊名：Biomacromolecules
• 出版年：2004
• 出版时间：July 2004
• 年：2004
• 卷：5
• 期：4
• 页码：1256 - 1261
• 全文大小：178K
• 年卷期：v.5,no.4(July 2004)
• ISSN：1526-4602

文摘

Synchrotron small-angle X-ray scattering was used to study the nanostructures of the complexes formed bycalf thymus DNA interacting with cationic lipids (or surfactants) of didodecyldimethylammonium bromide(DDAB), cetyltrimethylammonium bromide (CTAB), and their mixture with a zwitterionic lipid of1-palmitoyl-2-hydroxy-sn-glycero-3-phosphocholine (PHGPC). The effects of lipid/DNA ratios, DNA chainflexibility, lipid topology, and neutral lipid mixing on the nanostructures of DNA-lipid complexes wereinvestigated. The complexes between double-stranded DNA (dsDNA) and double-tailed DDAB formed abilayered lamellar structure, whereas the complexes between dsDNA and single-tailed CTAB preferred astructure of 2D hexagonal close packing of cylinders. With single stranded DNA (ssDNA) interacting withCTAB, the complexes showed a Pm3n cubic structure due to the different chain flexibility between dsDNAand ssDNA. The lipid molecules bound by rigid dsDNA like to form cylindrical micelles, whereas lipidsbound to flexible ssDNA could form spherical or short cylindrical micelles. The addition of the neutralsingle-chained PHGPC lipids to the CTAB lipids could induce a structural transition of dsDNA-lipidcomplexes from a 2D hexagonal to a multi-bilayered lamellar structure. The parallel DNA strands wereintercalated in the water layers of lamellar stacks of the mixed lipid bilayers. The DNA-DNA spacingdepended on the ratios of charged lipid to neutral lipid, and charged lipid to DNA, respectively.