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
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- 作者：Biswarup Saha ; Md. Maidul Islam ; Susmita Paul ; Saheli Samanta ; Shayoni Ray ; Chitta Ranjan Santra ; Somnath Ray Choudhury ; Biswajit Dey ; Amrita Das ; Somnath Ghosh ; Subrata Mukhopadhyay ; Gopinatha Suresh
- 刊名：Journal of Physical Chemistry B
- 出版年：2010
- 出版时间：May 6, 2010
- 年：2010
- 卷：114
- 期：17
- 页码：5851-5861
- 全文大小：401K
- 年卷期：v.114,no.17(May 6, 2010)
- ISSN：1520-5207
文摘
The DNA binding property of a Cu(II) complex, viz., [Cu(mal)2](picH)2·2H2O, (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 × 103 and 4.0 × 103 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 H2O2 it exhibits nuclease activity. The induction of the breakage in DNA backbone depends upon the relative concentrations of H2O2 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 H2O2. Further, 1H NMR study indicates that Cu(II) in the complex is converted into the Cu(I) state by the reduction of H2O2. 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.