ABSTRACT
Luminescence and binding properties of dysprosium(III) complex containing 1,10-phenanthroline (phen), [Dy(phen)2(OH2)3Cl]Cl2â H2O with DNA has been studied by electronic absorption, emission spectroscopy and viscosity measurement. The thermodynamic studies suggest that the interaction process to be endothermic and entropically driven, which indicates that the dysprosium(III) complex might interact with DNA by a non intercalation binding mode. Additionally, the competitive fluorescence study with ethidium bromide and also the effect of iodide ion and salt concentration on fluorescence of the complex-DNA system is investigated. Experimental results indicate that the Dy(III) complex strongly binds to DNA, presumably via groove binding mode. Furthermore, the complex shows a potent antibacterial activity and DNA cleavage ability.
Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , DNA/chemistry , Dysprosium/chemistry , Organometallic Compounds/chemistry , Organometallic Compounds/pharmacology , Phenanthrolines/chemistry , Animals , Binding Sites , Binding, Competitive , DNA Cleavage/drug effects , Iodides/chemistry , Ligands , Spectrometry, Fluorescence , Thermodynamics , ViscosityABSTRACT
Characterization of the interaction between yttrium(III) complex containing 1,10-phenanthroline as ligand, [Y(phen)2Cl(OH2)3]Cl2â H2O, and DNA has been carried out by UV absorption, fluorescence spectra and viscosity measurements in order to investigate binding mode. The experimental results indicate that the yttrium(III) complex binds to DNA and absorption is decreasing in charge transfer band with the increase in amount of DNA. The binding constant (Kb) at different temperatures as well as thermodynamic parameters, enthalpy change (ΔH°) and entropy change (ΔS°), were calculated according to relevant fluorescent data and Vant' Hoff equation. The results of interaction mechanism studies, suggested that groove binding plays a major role in the binding of the complex and DNA. The activity of yttrium(III) complex against some bacteria was tested and antimicrobial screening tests shown growth inhibitory activity in the presence of yttrium(III) complex.
Subject(s)
Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology , DNA/metabolism , Organometallic Compounds/metabolism , Organometallic Compounds/pharmacology , Phenanthrolines/chemistry , Yttrium/chemistry , Absorption , Anti-Bacterial Agents/chemistry , Bacteria/drug effects , Electrons , Ethidium/chemistry , Iodides/chemistry , Organometallic Compounds/chemistry , Osmolar Concentration , Thermodynamics , ViscosityABSTRACT
To evaluate the biological preference of [Yb(phen)2(OH2)Cl3](H2O)2 (phen is 1,10-phenanthroline) for DNA, interaction of Yb(III) complex with DNA in Tris-HCl buffer is studied by various biophysical and spectroscopic techniques which reveal that the complex binds to DNA. The results of fluorescence titration reveal that [Yb(phen)2(OH2)Cl3](H2O)2 has strongly quenched in the presence of DNA. The binding site number n, apparent binding constant K b, and the Stern-Volmer quenching constant K SV are determined. ΔH°, ΔS°, and ΔG° are obtained based on the quenching constants and thermodynamic theory (ΔH° > 0, ΔS° > 0, and ΔG° < 0). The experimental results show that the Yb(III) complex binds to DNA by non-intercalative mode. Groove binding is the preferred mode of interaction for [Yb(phen)2(OH2)Cl3](H2O)2 to DNA. The DNA cleavage results show that in the absence of any reducing agent, Yb(III) complex can cleave DNA. The antimicrobial screening tests are also recorded and give good results in the presence of Yb(III) complex.
Subject(s)
Anti-Infective Agents/chemistry , DNA/chemistry , Organometallic Compounds/chemistry , Phenanthrolines/chemistry , Ytterbium/chemistry , Anti-Infective Agents/pharmacology , Circular Dichroism , Microbial Sensitivity Tests , Organometallic Compounds/pharmacology , Thermodynamics , ViscosityABSTRACT
Fluorescence and absorption spectroscopy, circular dichroism (CD) as well as viscosity experiment have been used to characterize the DNA binding of [Ho(Phen)(2)Cl(3)]·H(2)O, where phen stand for 1,10-phanathroline. This complex exhibits the marked decrease in the emission intensity and some hypochromism in UV-Vis spectrum in the presence of DNA. For characterization of the binding mode between the Ho(III) complex and DNA various procedures such as: absorption and emission titration and EB quenching experiments, viscosity measurements, CD study, iodide quenching assay, salt effect and thermodynamical investigation are used. The intrinsic binding constant of [Ho(Phen)(2)Cl(3)]·H(2)O with DNA is calculated by UV-Vis and florescence spectroscopy. The value of binding constants in 296, 299 and 303 are 1.99 ± 0.07 × 10(4), 1.07 ± 0.09 × 10(4) and 0.84 ± 0.06 × 10(4), respectively. The thermodynamic studies show that the reaction is entropically driven. The above-mentioned physical measurements indicate that the Ho(III) complex binds to fish salmon DNA, presumably via groove binding mode.
