DNA binding and oxidative cleavage activity of ternary (L-proline)copper(II) complexes of heterocyclic bases

Rao, Ramakrishna and Patra, Ashis K and Chetana, PR (2007) DNA binding and oxidative cleavage activity of ternary (L-proline)copper(II) complexes of heterocyclic bases. In: Polyhedron, 26 (18). pp. 5331-5338.

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Abstract

Ternary copper(II) complexes $[Cu(L-pro)(B)(H_2O)](NO_3)$ (1, 2) where L-pro = L-proline, B is a N,N-donor heterocyclic base, viz. 2,2′-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2), are synthesized, characterized, and their DNA binding and cleavage activity studied. The bpy complex (1) is structurally characterized by single-crystal X-ray crystallography. The complexes show the presence of a distorted square-pyramidal $(4 + 1) CuN_3O_2$ coordination geometry. Complex $[Cu(L-pro)(bpy)(H_2O)](NO_3)$ (1) crystallizes in the triclinic space group P1 with unit cell parameters: a = 7.082(3) \AA, b = 10.483(5) \AA, c = 11.581(5) \AA, \alpha = 89.700(7)°, \beta = 83.488(8)°, \gamma = 84.109(8)° and V = 849.7(7)$ \AA^3$. The one-electron paramagnetic complexes display a d–d band near 600 nm in water and show a cyclic voltammetric response due to Cu(II)/Cu(I) couple near 0.1 V (versus SCE) in Tris–HCl buffer–0.1 M KCl. Binding interactions of the complexes with calf thymus (CT) DNA have been investigated by emission, absorption, viscosity and DNA thermal denaturation studies. The phen complex displays significant binding propensity to the CT DNA giving an order: 2 (phen) \gg 1 (bpy). The bpy complex does not show any apparent binding to the DNA and hence poor cleavage efficiency. Complex 2 shows efficient oxidative cleavage of SC-DNA in the presence of 3-mercaptopropionic acid (MPA) involving hydroxyl radical species as evidenced from the control data showing inhibition of DNA cleavage in the presence of DMSO and catalase.

Item Type:	Journal Article
Publication:	Polyhedron
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier.
Keywords:	Copper; DNA binding; DNA cleavage; Crystal structure; l-Proline; Phenanthroline base.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	21 Feb 2008
Last Modified:	19 Sep 2010 04:42
URI:	http://eprints.iisc.ac.in/id/eprint/13066

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