title: DNA binding ability and hydrogen peroxide induced nuclease activity of a novel Cu(II) complex with malonate as the primary ligand and protonated 2-amino-4-picoline as the counterion.
abstract: The DNA binding property of a Cu(II) complex, viz., [Cu(mal)(2)](picH)(2).2H(2)O, (mal)(2) = malonic acid, picH = protonated 2-amino-4-picoline, has been investigated in this study. The binding of this complex with plasmid and chromosomal DNA has been characterized by different biophysical techniques. From the absorption and fluorescence spectroscopic studies, it has been observed that the said copper complex binds strongly with pUC19 plasmid and CT DNA with a binding affinity of 2.368 x 10(3) and 4.0 x 10(3) M(-1), respectively, in 10 mM citrate-phosphate buffer, pH 7.4. Spectrofluorimetric studies reveal that the copper complex exhibits partial DNA intercalation as well as partial DNA minor groove binding properties. Consequently, in agarose gel electrophoresis study, it has been observed that the complex alone induces positive supercoiling in plasmid DNA while in the presence of H(2)O(2) it exhibits nuclease activity. The induction of the breakage in DNA backbone depends upon the relative concentrations of H(2)O(2) and copper complex followed by the time of incubation with DNA. Optical DNA melting study, isothermal titration calorimetry, and absorption spectroscopy have been used to characterize the nuclease activity of this complex in the presence of H(2)O(2). Further, (1)H NMR study indicates that Cu(II) in the complex is converted into the Cu(I) state by the reduction of H(2)O(2). Finally, agarose gel electrophoresis study with different radical scavengers concludes that the production of both hydroxyl radicals and reactive oxygen species is responsible for this nuclease activity.
authors.affiliation: Department of Life Science and Biotechnology, Jadavpur University, 188, Raja S.C. Mullick Road, Kolkata 700 032, West Bengal, India.
authors.forename: Biswarup
authors.initials: B
authors.lastname: Saha
authors.forename: Md Maidul
authors.initials: MM
authors.lastname: Islam
authors.forename: Susmita
authors.initials: S
authors.lastname: Paul
authors.forename: Saheli
authors.initials: S
authors.lastname: Samanta
authors.forename: Shayoni
authors.initials: S
authors.lastname: Ray
authors.forename: Chitta Ranjan
authors.initials: CR
authors.lastname: Santra
authors.forename: Somnath
authors.initials: S
authors.lastname: Ray Choudhury
authors.forename: Biswajit
authors.initials: B
authors.lastname: Dey
authors.forename: Amrita
authors.initials: A
authors.lastname: Das
authors.forename: Somnath
authors.initials: S
authors.lastname: Ghosh
authors.forename: Subrata
authors.initials: S
authors.lastname: Mukhopadhyay
authors.forename: Gopinatha Suresh
authors.initials: GS
authors.lastname: Kumar
authors.forename: Parimal
authors.initials: P
authors.lastname: Karmakar
mesh_terms: D002942:Circular Dichroism; D056831:Coordination Complexes / Q000737:chemistry*; D003300:Copper / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D003851:Deoxyribonucleases / Q000737:chemistry / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D006861:Hydrogen Peroxide / Q000737:chemistry*; D008024:Ligands; D008314:Malonates / Q000737:chemistry; D008968:Molecular Conformation; D010847:Picolines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D008314:Malonates; D010847:Picolines; C015672:2-amino-4-picoline; D003300:Copper; D004247:DNA; D006861:Hydrogen Peroxide; D003851:Deoxyribonucleases