Xingming Wang

Spectroscopic studies on the interaction between tryptophan-erbium(III) complex and herring sperm DNA.

By means of UV and fluorescence spectra, the binding ratios between Er(III)-Trp and DNA in physiological pH environment (pH 7.40) were determined as n(Trp):n(Er(III))=3:1 and (n)ER(III)(Trp)(3):(n)(DNA) = 2:1, and the apparent molar absorptivity of epsilon(Er(III)-Trp-DNA) is 4.33 x 10(5) L mol(-1)cm(-1) which was confirmed by molar ratio method. The binding constants at different temperatures K(B25 degrees C)(theta)=1.93 x 10(4)L mol(-1) and K(B37 degrees C)(theta)=5.28 x 10(3)L mol(-1) were obtained by double reciprocal method. Thermodynamic function computation demonstrates that Delta(r)H(m)(theta) is the primary driving power of the interaction between Er(III)(Trp)(3) and DNA. By combination analysis of the Scatchard method and CD spectrometry, we suggested that the interaction mode between Er(III)(Trp)(3) complex and herring sperm DNA is groove and intercalation bindings.

Synthesis and DNA Binding Studies of Mg(II) Complex of Schiff Base Derived from Vanillin and L-Tryptophan

The Mg(II) complex of Schiff base (K[HL]) derived from vanillin and L-tryptophan could bind with herring sperm DNA. The binding behaviors between them in physiological pH environment (pH 7.40) have been studied by spectroscopy, cyclic voltammetry and viscosity methods. Binding ratios of nMg(II): nK[HL] = 1:1 and nMg(II)L: nDNA = 5:1 were confirmed. The obtained thermodynamic parameters suggest that the interaction between Mg(II)L and DNA is driven mainly by entropy. Combined with fluorimeteric studies, cyclic voltammetry, CD spectroscopy and viscosity methods, the results indicate the interaction modes between Mg(II)L and DNA are mainly with intercalation and involving some electrostatic interaction.

STUDY ON THE INTERACTION BETWEEN THE INCLUSION COMPLEX OF HEMATOXYLIN WITH beta-CYCLODEXTRIN AND DNA

Ultraviolet-visible (UV-vis) spectra, fluorescence spectra, electrochemistry, and the thermodynamic method were used to discuss the interaction mode between the inclusion complex of hematoxylin with β-cyclodextrin and herring sperm DNA. On the condition of physiological pH, the result showed that hematoxylin and β-cyclodextrin formed an inclusion complex with binding ratio nhematoxylin:nβ-cyclodextrin = 1:1. The interaction mode between β-cyclodextrin-hematoxylin and DNA was a mixed binding, which contained intercalation and electrostatic mode. The binding ratio between β-cyclodextrin-hematoxylin and DNA was nβ-cyclodextrin -hematoxylin:nDNA = 2:1, binding constant was K⊖ 298.15K = 5.29 × 104 L·mol−1, and entropy worked as driven force in this action.

Spectroscopic studies on the interaction mechanisms of safranin T with herring sperm DNA using acridine orange as a fluorescence probe

Under the condition of physiological pH environment (pH = 7.40), the interactions of safranin T (ST) with herring sperm DNA were studied by means of spectral methods using acridine orange (AO) as a fluorescence probe. The spectroscopic characteristics of DNA–AO in the case of ST (along with the increase of concentration) were observed in an aqueous medium. The binding constants for ST stranded DNA and competitive bindings of ST interacting with DNA–AO systems were examined by fluorescence spectra, and the binding mechanism of ST with DNA was researched via viscosity measurements. All the testimony manifested that bonding modes between ST and DNA were evidenced to be intercalative binding and electrostatic binding, and the combining constant of ST with DNA was obtained. The binding of ST to DNA was driven by entropy and enthalpy through the calculated thermodynamic parameters (ΔrHmӨ, ΔrSm and ΔrGmӨ). Copyright

Interactions of Vitamin K3 with Herring-Sperm DNA Using Spectroscopy and Electrochemistry

By means of ultraviolet-visible (UV-Vis) and fluorescence spectra, the binding ratio between vitamin K3 and herring-sperm DNA in a physiological pH environment (pH = 7.40) was determined as nK3: nDNA = 2:1, and the binding constants of vitamin K3 binding to DNA at different temperatures were determined as Kθ298K = 1.28 × 105 L.mol−1 and Kθ310K = 7.19 × 104 L.mol−1, which were confirmed using the double reciprocal method are ΔrHmθ = −3.57 × 104 J.mol−1, ΔrGmθ = −2.92 × 104 J.mol−1, and ΔrSmθ = 217.67 J.mol−1K−1. The driving power of this process was enthalpy. An intercalation binding of the vitamin K3 with DNA was supported by a competitive experiment using acridine orange (AO) as a spectral probe. By combination analysis of the Scatchard method and cyclic voltammetry, we suggested that the interaction mode between vitamin K3 and herring-sperm DNA would be a mixed mode. The quinonoid, duality fused-ring of vitamin K3 can intercalate into the base pairs of DNA, and there is an electrostatic binding along with intercalation binding.

Interaction mode between Congo red-Sm(III) complex and herring sperm DNA

Spectroscopic and viscosity methods were applied to investigate the mechanism of interaction between Congo red (CR)–Sm(III) complex and herring sperm DNA by using acridine orange as a spectral probe in Tris-HCl buffer (pH 7.40). The binding ratio of Sm(III)(CR)3 : DNA is 5 : 1, the apparent molar absorptivity of Sm(III)(CR)3–DNA is 4.80 × 105 L (mol cm)−1 and the bonding constant of Sm(III)(CR)3 interacting with DNA is  = 1.11 × 107 L mol−1. The thermodynamic parameters are Δr  = 5.40 × 104 J mol−1, Δr  = 3.16 × 102 J (mol K)−1, Δr  = −4.03 × 104 J mol−1. The results confirm that the interaction between Sm(III)(CR)3 complex and DNA is a partial intercalation, and the reaction process is entropy favorable.

Spectroscopic investigations of hematoxylin–Eu(III) complex interacting with Herring-sperm DNA

The interaction of HE–Eu(III) complex (HE = hematoxylin) with Herring-sperm DNA (hsDNA) has been studied by absorption spectra, fluorescence, and viscosity measurements in physiological buffer (pH = 7.40). The binding constant of HE–Eu(III) complex to hsDNA was obtained by double reciprocal method at 298 and 310 K and the corresponding thermodynamic parameters (Δr Hm⊖ = 8.55 × 104 J mol−1, Δr Gm⊖ = −3.01 × 104 J mol−1, Δr Sm⊖ = 387.95 J mol−1 K−1) were calculated, showing that the interaction between HE–Eu(III) complex and hsDNA was driven mainly by entropy. The value of K indicated that the binding mode of HE–Eu(III) complex with DNA was not classical intercalation. These results were further supported by viscosity method and competitive binding experiment. Scatchard analysis suggests that the interaction mode was a mixed binding, which contains partial intercalation and groove binding.

DNA binding studies of hematoxylin-Dy(ш) complex by spectrometry using acridine orange as a probe.

The interaction of a hematoxylin(HE)-Dy(Ш) complex with herring sperm DNA(hsDNA) was studied using acridine orange(AO) as a probe by UV-vis absorption, circular dichroism(CD), fluorescence spectroscopy and viscosity measurements. From the results of the probe experiment, we found that the HE-Dy(Ш) complex could compete with AO for intercalating into hsDNA. The binding constants of the HE-Dy(Ш) complex to hsDNA was obtained by the double reciprocal method and indicated that the affinity between hsDNA and the complex is weaker than that between hsDNA and classical intercalators. The thermodynamic parameters(ΔH°, ΔG°, ΔS°) were calculated from the UV-vis absorption data measured at two different temperatures. Further experimental results suggested that there exist groove binding and partial intercalation binding between hsDNA and HE-Dy(Ш) complex.

Synthesis, Characterization, and DNA Interaction Studies of Dysprosium(III) with Methylene Blue

The interaction between methylene blue–Dy(III) complex and herring sperm DNA was investigated in physiological buffer (pH 7.40). The binding ratios and the apparent molar absorptivity of ϵ MB-Dy-DNA were determined by the molar ratio method. The thermodynamic parameters were calculated by a double-reciprocal equation at different temperatures, and showed that the interaction of methylene blue–Dy(III) complex with DNA was driven mainly by Δr S Θ m. By combination analysis of the Scatchard method, viscosity measurements, ferrocyanide quenching experiments, and circular dichroism spectroscopy, the methylene blue–Dy(III) complex can bind to DNA, and the major binding mode is electrostatic and partial intercalation binding.

Interaction Mode Between Methylene Blue-Pr(III) Complex and Herring-Sperm DNA

ABSTRACT By spectroscopic method, the binding ratios between methylene blue-Pr(III) and DNA in physiological pH environment (pH = 7.40) were determined as n Pr:n MB(III) = 1:3 and n Pr(III)(MB)3:n DNA = 8:1. The binding constants at different temperatures = 7.14 × 105 L · mol−1 and = 2.43 × 105 L · mol−1 were obtained by double reciprocal method. Thermodynamic function computation demonstrates that is the primary driving power of the interaction between Pr(III)(MB)3 and herring-sperm DNA. According to the analysis, we have evidenced that the interaction mode between Pr(III)(MB)3 complex and herring-sperm DNA is partial intercalation binding.