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

Chetana, PR and Rao, Ramakrishna and Roy, Mithun and Patra, Ashis K (2009) New ternary copper(II) complexes of L-alanine and heterocyclic bases: DNA binding and oxidative DNA cleavage activity. In: Inorganica Chimica Acta, 362 (13). pp. 4692-4698.

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Abstract

Four new ternary copper(II) complexes of alpha-amino acid having polypyridyl bases of general formulation [Cu(L-ala)(B)(H2O)](X)(1-4), where L-ala is L-alanine, B is an N,N-donor heterocyclic base, viz. 2,2'-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2) and 5,6-phenanthroline dione (dione, 3), dipyrido[3,2:2',3'-f] quinoxaline (dpq, 4), and X = ClO4-/NO3- are synthesized, characterized by various spectroscopic and X-ray crystallographic methods. The complexes show a distorted square-pyramidal (4 + 1) CuN3O2 coordination geometry. The one-electron paramagnetic complexes (1-4) display a low energy d-d band near 600 nm in aqueous medium and show a quasi-reversible cyclic voltammetric response due to one-electron Cu(II)/Cu(I) reduction near - 100 mV (versus SCE) in DMF-0.1 M TBAP. Binding interactions of the complexes with calf thymus DNA (CT-DNA) were investigated by UV-Vis absorption titration, ethidium bromide displacement assay, viscometric titration experiment and DNA melting studies. All the complexes barring the complexes 1 and 3 are avid binder to the CT-DNA in the DNA minor groove giving an order: 4 > 2 >>>1, 3. The complexes 2 and 4 show appreciable chemical nuclease activity in the presence of 3-mercaptopropionic acid (MPA) as a reducing agent. Hydroxyl radical was investigated to be the DNA cleavage active species. Control experiments in the presence of distamycin-A show primarily minor groove-binding propensity for the complexes 2 and 4 to the DNA.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier B. V.
Keywords: Ternary copper(II) complexes; L-Alanine; Crystal structure; DNA binding; Chemical nuclease activity; Hydroxyl radical
Department/Centre: Division of Chemical Sciences > Inorganic & Physical Chemistry
Depositing User: Id for Latest eprints
Date Deposited: 21 Dec 2009 06:24
Last Modified: 19 Sep 2010 05:50
URI: http://eprints.iisc.ac.in/id/eprint/24541

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