DNA binding and oxidative DNA cleavage activity of (μ-oxo)diiron(iii) complexes in visible light
- 17 December 2008
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Dalton Transactions
- No. 6,p. 1024-1033
- https://doi.org/10.1039/b815215b
Abstract
Four (μ-oxo)diiron(III) complexes [Fe2(μ-O)(H2O)2B4](ClO4)4 (1 and 2) and [Fe2(μ-O)(μ-O2CMe)B4](ClO4)3 (3 and 4), where B = 1,10-phenanthroline (phen) and dipyrido[3,2-d:2′,3′-f]quinoxaline (dpq), are prepared and their DNA binding and cleavage activity studied. The complexes show DNA binding propensity giving Kb values of 3.6–9.3 × 104 M−1. The viscosity and DNA melting data suggest a surface and/or groove binding nature of the complexes to calf thymus (CT) DNA. The DNA binding data obtained from isothermal calorimetric study indicate two binding modes involving surface aggregation and/or partial intercalation of the phenanthroline bases to CT DNA. All the complexes show chemical nuclease activity in the presence of 3-mercaptopropionic acid as a reducing agent following a mechanistic pathway that involves formation of superoxide and hydroxyl radicals. Photoirradiation of pUC19 DNA at 365 nm in the presence of 1–4 show that the complexes, barring 1, are efficient photocleavers of supercoiled DNA to its nicked circular form. Complexes 2–4 display photocleavage activity in visible light of different wavelengths. Complexes 3 and 4 exhibit significant DNA cleavage activity in red light of 633 nm, the wavelength known for the activity of the photodynamic therapeutic drug Photofrin®. The mechanistic study using various additives suggests a minor groove binding nature of the complexes with the formation of singlet oxygen from the quinoxaline moiety of dpq and hydroxyl radical from photodecarboxylation of the acetate ligand as the reactive oxygen species.Keywords
This publication has 101 references indexed in Scilit:
- Targeted Single-Wall Carbon Nanotube-Mediated Pt(IV) Prodrug Delivery Using Folate as a Homing DeviceJournal of the American Chemical Society, 2008
- DNA Cleavage on Photoexposure at the d−d Band in Ternary Copper(II) Complexes Using Red-Light LaserInorganic Chemistry, 2006
- New polyethyleneglycol-functionalized texaphyrins: synthesis and in vitro biological studiesDalton Transactions, 2006
- Microcalorimetry and binding studies of DNA upon interaction with [pyridine diamine]2[Co(phenanthroline dicarboxylate)2]Thermochimica Acta, 2005
- Cellular processing of platinum anticancer drugsNature Reviews Drug Discovery, 2005
- Iron Binding and Oxidation Kinetics in Frataxin CyaY of Escherichia coliJournal of Molecular Biology, 2004
- EPR studies of the photodynamic properties of a novel potential photodynamic therapeutic agent: photogeneration of semiquinone radical anion and active oxygen species (O2•−, OH•, H2O2 and 1O2)Published by Springer Science and Business Media LLC ,2003
- Evidence for chiral discrimination of ruthenium(ii) polypyridyl complexes by DNAElectronic supplementary information (ESI) available: absorption spectra. See http://www.rsc.org/suppdata/dt/b2/b208147d/Dalton Transactions, 2002
- Theoretical aspects of DNA-protein interactions: Co-operative and non-co-operative binding of large ligands to a one-dimensional homogeneous latticeJournal of Molecular Biology, 1974
- A Further Examination of the Molecular Weight and Size of Desoxypentose Nucleic AcidJournal of the American Chemical Society, 1954