The DNA–DNA spacing in gemini surfactants–DOPE–DNA complexes

作者：Petra Pullmannová; Sergio S Funari; Ferdinand Devínsky; Daniela Uhríková

来源：Biochimica et Biophysica Acta (BBA) - Biomembranes, 2012, 1818(11): 2725-2731.

DOI：10.1016/j.bbamem.2012.05.021

• DNA
• Dioleoylphosphatidylethanolamine
• Gemini surfactant
• Small angle X-ray diffraction

Gemini surfactants from the homologous series of alkane-α,ω-diyl-bis(dodecyldimethylammonium bromide) (CnCS12, number of spacer carbons n = 2 – 12) and dioleoylphosphatidylethanolamine (DOPE) were used for cationic liposome (CL) preparation. CLs condense highly polymerized DNA creating complexes. Small-angle X-ray diffraction identified them as condensed lamellar phase LαC in the studied range of molar ratios CnGS12/DOPE in the temperature range 20 – 60 °C. The DNA–DNA distance (dDNA) is studied in dependence to CnGS12 spacer length and membrane surface charge density. The high membrane surface charge densities (CnGS12/DOPE = 0.35 and 0.4 mol/mol) lead to the linear dependence of dDNA vs. n correlating with the interfacial area of the CnGS12 molecule.
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Highlights
► Cationic liposomes composed of CnGS12 gemini surfactant and DOPE condense DNA. ► We used CnGS12 with number of spacer carbons n = 2–12. ► The complexes CnGS12–DOPE–DNA form condensed lamellar phase LαC. ► The DNA–DNA spacing shows a linear dependence on n at CnGS12/DOPE = 0.35 and 0.4 mol/mol.