title: Conformational transition of DNA induced by cationic lipid vesicle in acidic solution: spectroscopy investigation.
abstract: The conformational transition of DNA induced by the interaction between DNA and a cationic lipid vesicle, didodecyldimethylammonium bromide (DDAB), had been investigated by circular dichroism (CD) and UV spectroscopy methods. We used singular value decomposition least squares method (SVDLS) to analyze the experimental CD spectra. Although pH value influenced the conformation of DNA in solution, the results showed that upon binding to double helical DNA, positively charged liposomes induced a conformational transition of DNA molecules from the native B-form to more compact conformations. At the same time, no obvious conformational changes occurred at single-strand DNA (ssDNA). While the cationic lipid vesicles and double-strand DNA (dsDNA) were mixed at a high molar ratio of DDAB vesicles to dsDNA, the conformation of dsDNA transformed from the B-form to the C-form resulting in an increase in duplex stability (DeltaT(m)=8+/-0.4 degrees C). An increasing in T(m) was also observed while the cationic lipid vesicles interacted with ssDNA.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, PR China.
authors.forename: Zheling
authors.initials: Z
authors.lastname: Zhang
authors.forename: Weimin
authors.initials: W
authors.lastname: Huang
authors.forename: Jilin
authors.initials: J
authors.lastname: Tang
authors.forename: Erkang
authors.initials: E
authors.lastname: Wang
authors.forename: Shaojun
authors.initials: S
authors.lastname: Dong
mesh_terms: D002412:Cations / Q000737:chemistry*; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002412:Cations; D004277:DNA, Single-Stranded; D008055:Lipids; D000644:Quaternary Ammonium Compounds; C046112:didodecyldimethylammonium; D004247:DNA