title: Binding and oxidative cleavage studies of DNA by mixed ligand Co(III) and Ni(II) complexes of quinolo [3,2-b]benzodiazapine and 1,10-phenanthroline.
abstract: Two mixed ligand complexes of the type [M(phen)(2)(qbdp)](PF(6))n.xH(2)O where M = Co(III) and Ni(II), qbdp = quinolo[3,2-b] benzodiazepine and phen = 1,10-phenanthroline, n = 3 or 2, x = 2 or 3 have been synthesized and characterized by employing analytical and spectral methods. The DNA binding property of the complexes with calf thymus-DNA has been investigated by using absorption spectra, viscosity measurements as well as thermal denaturation studies. The absorption spectral results indicate that the Co(III) and Ni(II) complexes intercalate between the base pairs of the DNA tightly with intrinsic DNA binding constant of 6.4 x 10(4) and 4.8 x 10(4) M(-1) in Tris HCl buffer containing 50 mM NaCl, respectively. The large enhancement in the relative viscosity of DNA on binding to the quinolo [3,2-b] benzodiazepine supports the proposed DNA binding modes. The complexes on reaction with super coiled (SC) DNA shows nuclease activity.
authors.affiliation: Department of P.G. Studies and Research in Industrial Chemistry, School of Chemical Sciences, Kuvempu University. Shankaraghatta, Karnataka. India.
authors.forename: M C
authors.initials: MC
authors.lastname: Prabhakara
authors.forename: H S Bhojya
authors.initials: HS
authors.lastname: Naik
authors.forename: V
authors.initials: V
authors.lastname: Krishna
authors.forename: H M
authors.initials: HM
authors.lastname: Kumaraswamy
mesh_terms: D001569:Benzodiazepines / Q000138:chemical synthesis / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D004247:DNA / Q000737:chemistry; D053837:DNA Cleavage / Q000187:drug effects; D007364:Intercalating Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D008024:Ligands; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D010084:Oxidation-Reduction / Q000187:drug effects; D010618:Phenanthrolines / Q000138:chemical synthesis / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods
chemical_list: D007364:Intercalating Agents; D008024:Ligands; D010618:Phenanthrolines; D001569:Benzodiazepines; D003035:Cobalt; D009532:Nickel; D004247:DNA; C427203:calf thymus DNA