title: The structural transition of DNA-Tris(1,10-phenanthroline) cobalt(III) complexes in ethanol-water solution.
abstract: The interaction of DNA with Tris(1,10-phenanthroline) cobalt(III) was studied by means of atomic force microscopy. Changes in the morphologies of DNA complex in the presence of ethanol may well indicate the crucial role of electrostatic force in causing DNA condensation. With the increase of the concentration of ethanol, electrostatic interaction is enhanced corresponding to a lower dielectric constant. Counterions condense along the sugar phosphate backbone of DNA when epsilon is lowered and the phosphate charge density can thus be neutralized to the level of DNA condensation. Electroanalytical measurement of DNA condensed with Co(phen)(3)(3+) in ethanol solution indicated that intercalating reaction remains existing. According to both the microscopic and spectroscopic results, it can be found that no secondary structure transition occurs upon DNA condensing. B-A conformation transition takes place at more than 60% ethanol solution.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Zheng
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Li
authors.forename: Aiguo
authors.initials: A
authors.lastname: Wu
authors.forename: Hualan
authors.initials: H
authors.lastname: Zhou
authors.forename: Hanying
authors.initials: H
authors.lastname: Bai
authors.forename: Yonghai
authors.initials: Y
authors.lastname: Song
mesh_terms: D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure*; D000431:Ethanol / Q000737:chemistry; D046911:Macromolecular Substances; D018625:Microscopy, Atomic Force; D009690:Nucleic Acid Conformation; D009942:Organometallic Compounds / Q000737:chemistry* / Q000378:metabolism; D010618:Phenanthrolines / Q000737:chemistry* / Q000378:metabolism; D012997:Solvents / Q000737:chemistry; D055672:Static Electricity; D014867:Water / Q000737:chemistry
chemical_list: D046911:Macromolecular Substances; D009942:Organometallic Compounds; D010618:Phenanthrolines; D012997:Solvents; D014867:Water; C035551:triphenanthrolinecobalt(III); D000431:Ethanol; D004247:DNA