scholarly journals DNA Interaction and DNA Cleavage Studies of a New Platinum(II) Complex Containing Aliphatic and Aromatic Dinitrogen Ligands

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Nahid Shahabadi ◽  
Soheila Kashanian ◽  
Maryam Mahdavi ◽  
Noorkaram Sourinejad

A new Pt(II) complex, [Pt(DIP)(LL)](NO3)2(in which DIP is 4,7-diphenyl-1,10-phenanthroline and LL is the aliphatic dinitrogen ligand,N,N-dimethyl-trimethylenediamine), was synthesized and characterized using different physico-chemical methods. The interaction of this complex with calf thymus DNA (CT-DNA) was investigated by absorption, emission, circular dichroism (CD), and viscosity measurements. The complex binds to CT-DNA in an intercalative mode. The calculated binding constant,Kb, was  M−1. The enthalpy and entropy changes of the reaction between the complex and CT-DNA showed that the van der Waals interactions and hydrogen bonds are the main forces in the interaction with CT-DNA. In addition, CD study showed that phenanthroline ligand insert between the base pair stack of double helical structure of DNA. It is remarkable that this complex has the ability to cleave the supercoiled plasmid.

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Peiran Zhao ◽  
Shanshan Zhai ◽  
Jianfang Dong ◽  
Lei Gao ◽  
Xinru Liu ◽  
...  

Three hexacoordinated octahedral nickel(II) complexes, [Ni(sal-L-phe)(phen)(CH3OH)]⋅CH3OH (1), [Ni(naph-L-phe)(phen)(CH3OH)] (2), and [Ni(o-van-L-phe)(phen)(CH3OH)]⋅5CH3OH (3) (sal-L-phe = a Schiff base derived from salicylaldehyde and L-phenylalanine, naph-L-phe = a Schiff base derived from 2-hydroxy-1-naphthaldehyde and L-phenylalanine, o-van-L-phe = a Schiff base derived from o-vanillin and L-phenylalanine, and phen = 1,10-phenanthroline), have been synthesized and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. The interactions of these complexes with CT-DNA were studied by UV-Vis absorption spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy, and viscosity measurements. The binding constant (Kb) values of 1.82 × 104 M−1 for 1, 1.96 × 104 M−1 for 2, and 2.02 × 104 M−1 for 3 suggest that each of these complexes could bind with DNA in a moderate intercalative mode. Complex 3 exhibited a stronger interaction with CT-DNA than complexes 1 and 2. In addition, the superoxide scavenging activity of these complexes was investigated by the nitrotetrazolium blue chloride (NBT) light reduction method, and the results showed that they exhibited a significant superoxide scavenging activity with the IC50 values of 4.4 × 10−5 M for complex 1, 5.6 × 10−5 M for complex 2, and 3.1 × 10−5 M for complex 3, respectively.


2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Nahid Shahabadi ◽  
Somaye Mohammadi ◽  
Robabeh Alizadeh

A new mononuclear Pt(II) complex, [Pt(DMP)(DIP)]Cl2.H2O, in which DMP is 4,4-dimethyl-2,2-bipyridine and DIP is 4,7-diphenyl-1,10-phenantroline, has been synthesized and characterized by physicochemical and spectroscopic methods. The binding interaction of this complex with calf thymus DNA (CT-DNA) was investigated using fluorimetry, spectrophotometry, circular dichroism, viscosimetry and cyclic voltametry (CV). UV-VIS spectrum showed 4 nm bathochromic shift of the absorption band at 280 nm along with significant hypochromicity for the absorption band of the complex. The intrnisic binding constant is more in keeping with intercalators and suggests this binding mode. The viscosity measurements showed that the complex-DNA interaction can be hydrophobic and confirm intercalation. Moreover, the complex induced detectable changes in the CD spectrum of CT-DNA. The fluorescence studies revealed that the probable quenching mechanism of fluorescence of the complex by CT-DNA is static quenching. The thermodynamic parameters ( and ) showed that main interaction with hydrogenic forces occurred that is intercalation mode. Also, CV results confirm this mode because, with increasing the CT-DNA concentration, shift to higher potential was observed.


2011 ◽  
Vol 26 (4-5) ◽  
pp. 289-296
Author(s):  
Fei Ma ◽  
Jing Tang ◽  
Chao Yang ◽  
Yu-Ying Feng ◽  
Shao-Hua Wei ◽  
...  

The interaction of Elsinochrome A (EA) with calf thymus DNA (CT-DNA) has been investigated by UV-vis spectra and fluorescence spectra. The results show that EA can bind with CT-DNA and binding sites are destroyed after irradiation by visible light, which indicates that EA is a promising candidate for photodynamic therapy. In addition, the binding mechanism is studied using fluorescence quenching test and ethidium bromide (EB) replace assay experiments. The results suggest that EA and CT-DNA are binding with a strong force and the major binding mode of EA with DNA could be the electrostatic binding.


2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Raj Kaushal ◽  
Sheetal Thakur ◽  
Kiran Nehra

Five structurally related titanium (IV) heteroleptic complexes, [TiCl2(bzac)(L1–4)] and [TiCl3(bzac)(HL5)]; bzac = benzoylacetonate; L1–5 = benzohydroximate (L1), salicylhydroximate (L2), acetohydroximate (L3), hydroxyurea (L4), and N-benzoyl-N-phenyl hydroxylamine (L5), were used for the assessment of their antibacterial activities against ten pathogenic bacterial strains. The titanium (IV) complexes (1–5) demonstrated significant level of antibacterial properties as measured using agar well diffusion method. UV-Vis absorption spectroscopic technique was applied, to get a better insight into the nature of binding between titanium (IV) complexes with calf thymus DNA (ct-DNA). On the basis of the results of UV-Vis absorption spectroscopy, the interaction between ct-DNA and the titanium (IV) complexes is likely to occur through the same mode. Results indicated that titanium (IV) complex can bind to calf thymus DNA (ct-DNA) via an intercalative mode. The intrinsic binding constant (Kb) was calculated by absorption spectra by using Benesi-Hildebrand equation. Further, Gibbs free energy was also calculated for all the complexes.


2009 ◽  
Vol 13 (08n09) ◽  
pp. 964-972 ◽  
Author(s):  
Hamid Dezhampanah ◽  
Abdol-Khalegh Bordbar ◽  
Shahram Tangestaninejad

Binding properties of two water-soluble porphyrins, manganese(III) 5-(1-(4-carboxybutyl)pyridinium-4-yl) 10,15,20-tris(1-methylpyridinium-4-yl)porphyrin ( Mn(III)5-CBPyP ) and manganese(III) 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin ( Mn(III)TMPyP ), in the presence of various concentration of calf thymus DNA (ct-DNA), has been studied in 7.5 mM phosphate buffer, pH = 7.2 and at various temperatures by UV-vis absorption, resonance light scattering (RLS) and fluorescence spectroscopy and viscosity measurement. Optical absorption and RLS measurements have demonstrated three different species of both porphyrins form in DNA solution. The thermodynamic parameters were calculated by van't Hoff equation at various temperatures. The values of -4.89 kJ.mol-1 and +65.98 J.mol-1.K-1 for Mn(III)5-CBPyP and -14.92 kJ.mol-1 and +15.46 J mol-1.K-1 for TMPyP were estimated for enthalpy and entropy changes of interaction, respectively. The data indicate that the process is exothermic and enthalpy- and entropy-driven, suggesting that electrostatic forces play a considerable role in the interaction process. The binding of both porphyins to DNA quenches fluorescence emission of ethidium bromide (EB) and the quenching process obeys linear Stern-Volmer relationship, indicating the quenching of electron transfer of EB from its binding sites by these porphyrins. The results of using these techniques indicate the external mode of binding for both porphyrins and a higher binding affinity of Mn(III)5-CBPyP with respect to Mn(III)TMPyP .


2009 ◽  
Vol 7 (1) ◽  
pp. 105-110 ◽  
Author(s):  
Jian-Ping Cheng ◽  
Qiu-Yue Lin ◽  
Hu Rui-Ding ◽  
Wen-Zhong Zhu ◽  
Hua-Qiong Li ◽  
...  

AbstractTwo novel complexes, [La(HL)(H2O)2NO3] · NO3 · H2O and [Gd(HL)(H2O)2NO3] · NO3 · H2O, where HL is a Schiff base derived from o-vanillin and lysine, have been synthesized and characterized by elemental analysis, conductivity measurements, IR, 1H NMR and thermogravimetric analyses (TGA). The Schiff base ligand behaves as a tetradentate, coordinating through azomethine nitrogen, phenolic oxygen and two carboxylic oxygen atoms. The interaction of these complexes with calf thymus DNA (CT-DNA) was also investigated by spectrometric titration and viscometric measurements. The faint hypochromism of the complexes in the absorption spectra, the remarkable reduction of fluorescence intensity of ethidium bromide (EB) bound DNA, together with a small decrease in the viscosity of the DNA suggest that a partial intercalation may be the preferred binding mode between these two complexes and DNA. The antibacterial activity testing revealed that the complexes and their precursor Schiff base show a weak to moderate activity against Bacillus subtilis, Staphylococcus aureus and Escherichia coli.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Reza Hajian ◽  
Tan Guan Huat

The ds-DNA binding properties of irinotecan (CPT-11) including binding constant, thermodynamic parameter, and thermal denaturation (Tm) have been systematically studied by spectrophotometric methods. The binding of CPT-11 to ds-DNA is quite strong as indicated by its remarkable hypochromicity and equilibrium binding constant (Kb). The van't Hoff plot of 1/Tversus ln Kbsuggests that the CPT-11 binds endothermically to ct-DNA which is characterized by large positive enthalpy and entropy changes. According to the polyelectrolyte theory, the charge release (Z), when ct-DNA interacts with CPT-11, is +0.98, which corresponds very well to the one positive charge carried by CPT-11. TheKbat a low concentration of salt is dominated by electrostatic interaction (98.5%) while that at a high concentration of salt is weakly controlled by nonelectrostatic processes (19.0%). A moderate stabilization of the double helix ds-DNA occurs when CPT-11 binds to ds-DNA as indicated by the increase inTmof ct-DNA by approximately 15°C in the presence of CPT-11. The CPT-11 is stabilized by intercalation in the DNA (binding constant,K[irinotecan-DNA] = 5.8 × 104 mol−1 L) and displaces the NR dye from the NR-DNA complex (K[NR-DNA] = 2.7 × 104 mol−1 L) in a competitive reaction.


1984 ◽  
Vol 32 (9) ◽  
pp. 3636-3640 ◽  
Author(s):  
NARIKO SHINRIKI ◽  
KOZO ISHIZAKI ◽  
SHOKO SATO ◽  
KAZUNOBU MIURA ◽  
KAZUYUKI SAWADAISHI ◽  
...  

2009 ◽  
Vol 23 (3-4) ◽  
pp. 155-163 ◽  
Author(s):  
Cristina M. Muntean ◽  
Konstantinos Nalpantidis ◽  
Ingo Feldmann ◽  
Volker Deckert

The influence of Zn2+ions on the structure of natural calf thymus DNA was studied by Raman spectroscopy. Measurements were done at room temperature and pH 6.2±0.1, in the presence of 10 mM Na+, and of Zn2+in a concentration range varying between 0 and 250 mM, respectively. No condensation of DNA was observed.As judging from the marker bands near 681 cm−1(dG), 729 cm−1(dA), 752 cm−1(dT), and 787 cm−1(dC, dT) altered nucleoside conformations in these residues are supposed to occur, in different intervals of Zn2+ions concentration. Changes in the conformational marker centered around 835 cm−1, upon Zn2+binding to DNA, were detected. Binding of zinc(II) ions to the charged phosphate groups of DNA, stabilizing the double helical structure, is indicated in the spectra. We have found that binding of metal ions at N3 of cytosine takes place at zinc(II) concentrations between 150–250 mM and interaction of Zn2+ions with adenine is observed in a concentration range from 10 to 250 mM. Binding of zinc(II) ions to N7 of guanine and, possibly, in a lesser extent to adenine was also observed as indicated by the Raman marker bands near 1490 and 1581 cm−1. There is no intensity change of the band at 1668 cm−1, suggesting no change in their base pairing and no change induced in the structure of water by Zn2+cations. No evidence for DNA melting was identified.


Author(s):  
Nagaraj Karuppiah ◽  
◽  
Muthukumaran Pakkirisamy ◽  
Gunasekaran Gladwin ◽  

The interaction of cis-[Co(phen)2(TA)2](ClO4)3, a cationic surfactant complex (phen = 1-10 phenanthroline, TA= Tetradecylamine), with calf thymus DNA has been studied by physici-chemical techniques. The spectroscopic studies together with cyclic voltammetry and viscosity experiments support that the surfactant-cobalt(III) complex binds to calf thymus DNA (CT DNA) by intercalation through the aliphatic chain present in the complex into the base pairs of DNA. The presence of phenanthroline ligand with larger -frame work may also enhance intercalation. Besides the effect of binding of surfactant cobalt(III) complex to DNA in presence of -cyclodextrin has also studied. In presence of -cyclodextrin the binding occur through surface and (or) groove binding. The complex was investigated as one of the potential


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