共查询到20条相似文献,搜索用时 31 毫秒
1.
A new copper(II) complex, [Cu(Bphen)(Leu)(NO3)(H2O)] (Bphen = 4,7-diphenyl-1,10-phenanthroline, leu = L-leucine), has been synthesized and characterized by IR spectroscopy, CHN analysis, and single-crystal X-ray diffraction techniques. The CT-DNA binding properties of the complex have been investigated by both absorption and emission spectroscopy. The binding parameters for the fluorescence Scatchard plot were also determined. Further, the interaction of the complex with bovine serum albumin (BSA) has been investigated using absorption and emission spectroscopy. The thermodynamic parameters, free energy change (ΔG), enthalpy change (ΔH), and entropy change (ΔS), were calculated by the van’t Hoff equation and discussed. The distance between BSA and the complex has been obtained according to fluorescence resonance energy transfer. Conformational changes of BSA have been observed from synchronous fluorescence. Antioxidant and radical scavenging activities of the complex were determined by various in vitro assays such as 1,1-diphenyl-2-picryl-hydrazyl free radicals (DPPH˙), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radicals (ABTS˙+), and reducing ability determination by H2O2 scavenging methods. 相似文献
2.
《Physics and Chemistry of Liquids》2012,50(2):127-133
The binding of potassium dodecatangestato cobaltate(III) (PDC) as a water-soluble polyoxometal with bovine serum albumin (BSA) as a major transporting protein of plasma, has been investigated at pH 7.2, 5?mM phosphate buffer, 27°C and various ionic strength by fluorescence spectroscopy. The results show that the binding of PDC to BSA quenches BSA emission and the Stern–Volmer linear relationship can be applied for the quenching process. The values of Stern–Volmer constant, K sv, which can be considered as a binding constant for formation of 1:1 complex at 0.01, 0.1 and 0.2?M NaCl are 8.56 × 105, 5.72 × l05 and 9.60 × 105, respectively. The interpretation of the results represents that binding affinity depends on both electrostatic forces and conformational stability of BSA. A step-by-step aggregation model, which has been developed by Borissevich et al., was used to determine the average aggregation number of BSA, ?J?, from the fluorescence quenching. The results show that the binding of PDC to BSA does not induce any considerable aggregation in BSA molecules. Therefore, it can be concluded that there are no considerable conformational changes in BSA molecules during its interaction with PDC. 相似文献
3.
《Journal of Coordination Chemistry》2012,65(16):2919-2934
[C20H32Cu2I3N4] n was synthesized and characterized by elemental analysis, ESI-MS spectrometry, and IR spectra. The crystal structure was determined by X-ray single-crystal diffraction. The binding of the complex with bovine serum albumin (BSA) was studied by fluorescence spectroscopy under simulated physiological conditions. The binding constant (K b), the number of binding sites (n), and the corresponding thermodynamic parameters ΔH, ΔS, ΔG were calculated based on the van’t Hoff equation. The complex had strong ability to quench the fluorescence from BSA, and the quenching mechanism of this complex to BSA was static quenching. Hydrogen bonds and van der Waals forces are the interactions between the Cu(I/II) complex and BSA. According to the Förster non-radiation energy transfer theory, the binding average distance between the donor (BSA) and the acceptor (Cu(I/II) complex) was obtained. The effect of the complex on the BSA conformation was also studied by using synchronous fluorescence spectroscopy. 相似文献
4.
本文通过吸收和荧光光谱法研究了一种噻菁染料与人血清蛋白及牛血清蛋白的相互作用。吸收光谱数据表明,与血清蛋白结合后,噻菁染料单体的吸收峰发生红移,同时强度也有很大变化;还通过吸收光谱计算确定了噻菁染料与血清蛋白的结合位点数( n )。与人血清蛋白或牛血清蛋白结合后,噻菁染料的荧光量子产率增加。分析噻菁染料的荧光强度随溶液中血清蛋白浓度的变化得到了二者反应的表观结合常数( K a)和自由能变化( ΔG )。根据表观结合常数( K a)可以判断,人血清蛋白比牛血清蛋白与噻菁染料的结合更强。 相似文献
5.
Yan Gao Saimeng Zhang Xiaoguang Li Shuyao Jiang Yajing Yang Xiaohong Chang 《应用有机金属化学》2020,34(2):e5330
Salicylaldimine-bridged dinuclear cyclopalladated complexes were synthesized by the reactions of cyclopalladated chloro dimers [Pd{(4-R)C6H3CH=N-C6H3–2,6-i-Pr2}(μ-Cl)]2 (R = H; OMe) with salen-based bridging ligands. The complexes were characterized by FTIR, NMR spectroscopy, elemental analysis and X-ray crystallography. The binding interaction of cyclopalladated complexes to bovine serum albumin (BSA) was investigated by UV–vis, fluorescence and synchronous fluorescence spectroscopy. The experimental results showed that these Pd (II) complexes could bind to BSA with high affinity and quench its intrinsic fluorescence by a static or combined process. Also the interaction of Pd complexes with BSA affected the conformation of the tryptophan and tyrosine residues. 相似文献
6.
Zhang G Wang L Fu P Hu M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,82(1):424-431
The mechanism and conformational changes of farrerol binding to bovine serum albumin (BSA) were studied by spectroscopic methods including fluorescence quenching technique, UV–vis absorption, circular dichroism (CD) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy under simulative physiological conditions. The results of fluorescence titration revealed that farrerol could strongly quench the intrinsic fluorescence of BSA through a static quenching procedure. The thermodynamic parameters enthalpy change and entropy change for the binding were calculated to be −29.92 kJ mol−1 and 5.06 J mol−1 K−1 according to the van’t Hoff equation, which suggested that the both hydrophobic interactions and hydrogen bonds play major role in the binding of farrerol to BSA. The binding distance r deduced from the efficiency of energy transfer was 3.11 nm for farrerol–BSA system. The displacement experiments of site markers and the results of fluorescence anisotropy showed that warfarin and farrerol shared a common binding site I corresponding to the subdomain IIA of BSA. Furthermore, the studies of synchronous fluorescence, CD and FT-IR spectroscopy showed that the binding of farrerol to BSA induced conformational changes in BSA. 相似文献
7.
Hua Yan Songlin Zhao Jianguo Yang Xiandi Zhu Guoliang Dai Huading Liang Fuyou Pan Lin Weng 《Journal of solution chemistry》2009,38(9):1183-1192
The interaction between levamisole hydrochloride (LH) and bovine serum albumin, BSA, has been studied by a spectral method
under physiological conditions. For 1:n complexes, the relationship between fluorescence quenching intensity and concentration of the quenchers can be deduced on
the basis of the modified Stern–Volmer equation. The binding constants and corresponding thermodynamic parameters ΔH
m, ΔG
m and ΔS
m at different temperatures were calculated. The experimental results demonstrated that the combination reaction of LH and
BSA was a static quenching process because a 1:1 complex was formed, and the main dominant binding forces were hydrogen bonding
and van der Waals forces. Meanwhile, the polarity of the tyrosine residue (Tyr) or tryptophan residue (Trp) micro-region was
not obviously affected by the interaction. Furthermore, the binding constant increase when alcohol was added. 相似文献
8.
Ling-Ling He Xin Wang Bin Liu Jun Wang Ya-Guang Sun 《Journal of solution chemistry》2010,39(5):654-664
The interaction between ranitidine hydrochloride (RAN) and bovine serum albumin (BSA) in aqueous solution was investigated
by means of fluorescence, synchronous fluorescence, and UV-Vis spectroscopy. The fluorescence of BSA was quenched remarkably
by RAN and the quenching mechanism was concluded to be static quenching. The binding constants K and the number of binding sites n were calculated at three different temperatures. The RAN–BSA binding distance was determined to be less than 8 nm, suggesting
that energy transfer may occur from BSA to RAN. The interaction process is spontaneous. Based on the obtained thermodynamic
parameters, electrostatic forces may play a major role in this process. In addition, the effect of RAN on the conformation
of BSA was analyzed using synchronous fluorescence spectra. 相似文献
9.
《应用有机金属化学》2017,31(10)
[Pd(L1)(C,N)]CF3SO3 and [Pd(L2)(C,N)]CF3SO3 (L1 = 2,2′ ‐bipyridine, L2 = 1,10‐phenanthroline and C,N = benzylamine) novel orthopalladated complexes have been synthesized and characterized using various techniques. The binding of the complexes with native calf thymus DNA (CT‐DNA) was monitored using UV–visible absorption spectrophotometry, fluorescence spectroscopy and thermal denaturation studies. Our results indicate that these complexes can strongly bind to CT‐DNA via partial intercalative mode. In addition, fluorescence spectrometry of bovine serum albumin (BSA) with the complexes shows that the fluorescence quenching mechanism of BSA is a static process. The results of site‐competitive replacement experiments with specific site markers clearly indicate that the complexes bind to site I of BSA. Notably, the complexes exhibit significant in vitro cytotoxicity against two human cancer cell lines (Jurkat and MCF‐7) with IC50 values varying from 37 to 53 μM. Finally, a molecular docking experiment effectively proves the binding of the Pd(II) complexes to DNA and BSA. 相似文献
10.
The interaction between colloidal AgTiO2 nanoparticles and bovine serum albumin (BSA) was studied by using absorption, steady state, time resolved and synchronous fluorescence spectroscopy measurements. Absorption spectroscopy proved the formation of a ground state BSA?AgTiO2 complex. Upon excitation of BSA, colloidal AgTiO2 nanoparticles effectively quenched the intrinsic fluorescence of BSA. The number of binding sites (n = 1.06) and apparent binding constant (K = 3.71 × 105 M−1) were calculated by the fluorescence quenching method. A static mechanism and conformational changes of BSA were observed. 相似文献
11.
Shuhong Cao Dandan Wang Xiaoyan Tan Jingwen Chen 《Journal of solution chemistry》2009,38(9):1193-1202
The interaction between trans-resveratrol (TR) with bovine serum albumin (BSA) in aqueous solution was investigated by means of fluorescence, synchronous
fluorescence and infrared spectroscopy. The fluorescence of BSA can be quenched remarkably by TR in aqueous solution. A notable
red-shift of the maximum emission of BSA from 340 to 353 nm together with appearance of an isoemissive point at 395 nm were
observed. The results indicate that TR binds to BSA, forming a TR–BSA complex. The TR–BSA binding distance was determined
to be less than 7 nm, suggesting that energy transfer from BSA to TR may occur. The interaction process is spontaneous. Based
on the obtained thermodynamic parameters, electrostatic forces may play a major role in this process. Both synchronous fluorescence
and FT-IR spectra confirmed the interaction, and indicate the conformational changes of BSA. 相似文献
12.
F. Tavakolyanpour S. Waqif Husain M. H. Rastegar M. Saber Tehrani P. Abroomand Azar A. A. Momtazi Borojeni S. Alireza Esmaeili 《Journal of the Iranian Chemical Society》2016,13(11):2121-2133
DNA and BSA binding properties of mononuclear Co (II) and Cu (II) complexes containing letrozole [M(Le)4Cl2]·(H2O)](Le=[4,4-(1H-1,2,4-triazol-1-ylmethylene)bisbenzonitrile] have been investigated under physiological conditions. The interaction ability of the two complexes with native calf thymus DNA(CT-DNA) has been monitored as a function of the metal complex-DNA molar ratio by UV–Vis absorption spectrophotometry, fluorescence spectroscopy, circular dichroism(CD) and thermal denaturation studies. The intrinsic binding constants, Kb, of complexes 1 and 2 with CT-DNA, obtained from UV–Vis absorption studies, were 3.15 ± 0.02 × 104 and 4.37 ± 0.02 × 104 M?1, respectively. The addition of the complexes to CT-DNA (1:2) leads to an increase in the melting temperature of DNA up to around 4 °C, which has revealed that complexes could interact with DNA through intercalation mode. Fluorimetric studies have been performed using methylene blue (MB) as a fluorescence probe and competitive studies have shown the ability of the complexes to displace the DNA-bound MB, suggesting competition with MB. To explore the potential biological value of the complexes, the binding interaction between Co (II) and Cu (II) complexes and bovine serum albumin (BSA) has also been studied by fluorescence spectroscopy. The results indicate that the reaction between the complexes and BSA is a static quenching procedure. The site marker displacement experiment has suggested the location of the complexes binding to BSA at Sudlow’s site I in subdomain IIA. Finally, MTT assay studies have shown that the bioactive complexes exert significantly high selective dose-dependent cytotoxicity against a panel of cancer cell lines including MCF-7, JURKAT, SKOV3 and U87. 相似文献
13.
The binding interaction of a Schiff base compound containing a 1,2,4‐triazole ring [4‐(4‐chlorobenzyl‐ideneamino)‐5‐methyl‐1,2,4‐triazole‐3‐thiol, CTT] with bovine serum albumin (BSA) was studied by spectroscopy methods including fluorescence and circular dichroism spectrum under simulative physiological conditions. Fluorescence investigation revealed that the fluorescence quenching of BSA was induced by the formation of a relative stable CTT‐BSA complex. The corresponding binding constants (Ka) between CTT and BSA at three different temperatures were calculated according to the modified Stern‐Volmer equation. The enthalpy change (ΔH⊖) and entropy change (ΔS⊖) were calculated to be −15.78 kJ·mol−1 and 49.23 J·mol−1·K−1, respectively, which suggested that hydrophobic forces and hydrogen bond played major roles in stabilizing the CTT‐BSA complex. Site marker competitive experiments indicated that the binding of CTT to BSA primarily took place in sub‐domain IIIA (site II) of BSA. The binding distance (r) between CTT and the tryptophan residue of BSA was obtained to be 4.3 nm based on F?rster theory of non‐radioactive energy transfer. The conformational investigation revealed that the presence of CTT decreased the α‐helix content of BSA (from 58.62% to 54.66%) and induced the slight unfolding of the polypeptides of protein, which confirmed some micro‐environmental and conformational changes of BSA molecules. 相似文献
14.
《Journal of Coordination Chemistry》2012,65(4):722-739
Some new water-soluble Schiff-base complexes Na2[M(5-SO3-2,3-salpyr)(H2O) n ]?·?2H2O (5-SO3-2,3-salpyr?=?N,N′-bis(5-sulphosalicyliden)-2,3-diaminopyridine and M?=?Zn, Cu, Ni) were synthesized and characterized by elemental analysis, IR, 1H NMR, magnetic susceptibility measurement, thermal analysis, and UV-Vis spectroscopy. The mechanism of binding of Na2[M(5-SO3-2,3-salpyr)(H2O) n ]?·?2H2O with bovine serum albumin (BSA) was investigated by fluorescence spectroscopy. The fluorescence titration revealed that the intrinsic fluorescence of BSA was quenched by Na2[M(5-SO3-2,3-salpyr)], which was rationalized in terms of the static quenching mechanism. The values of the Stern–Volmer constants, quenching rate constants, binding constants, binding sites, and average aggregation number of BSA were determined by this method. Thermodynamic parameters were calculated by the van’t Hoff equation. The data clearly indicate that the binding is entropy driven and enthalpically disfavored. Based on the Förster theory of non-radiative energy transfer, the efficiency of energy transfer, and the distance between the donor (Trp residues) and the acceptor (Na2[M(5-SO3-2,3-salpyr)]) were evaluated. Also the synchronous fluorescence spectra showed that the microenvironment of the tryptophan residues was not changed. Finally, our results indicate that the complexes can bind to BSA and be efficiently transported in the body, which could be helpful for further drug design. 相似文献
15.
Dan Wu Guiying Xu Yujun Feng Yajing Wang Yanyan Zhu 《Colloid and polymer science》2009,287(2):225-230
The interaction between bovine serum albumin (BSA) with N, N′-bis(dimethylalkyl) ethylammonium dibromide (C12C2Cm, m = 8, 12) was investigated by spectral methods. It can be seen that C12C2C8 and C12C2C12 mainly interact with tryptophan residues of BSA from synchronous fluorescence spectra. Fluorescence, far-UV, and near-UV
circular dichrosim spectra of BSA are changed by addition of dissymmetric and symmetric gemini surfactant. For surfactant
solution, the polarity of the microenvironment surrounding pyrene is lower while the fluorescence lifetime of it is longer
and the microviscosity is higher in the presence of BSA than those in the absence of BSA. But compared with C12C2C12, C12C2C8 has lower binding ability with BSA due to the shorter hydrophobic tail and lower symmetry. 相似文献
16.
Ratiometric Fluorescence Imaging of Cellular Polarity: Decrease in Mitochondrial Polarity in Cancer Cells
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Na Jiang Jiangli Fan Feng Xu Prof. Xiaojun Peng Huiying Mu Prof. Jingyun Wang Xiaoqing Xiong 《Angewandte Chemie (International ed. in English)》2015,54(8):2510-2514
Mitochondrial polarity strongly influences the intracellular transportation of proteins and interactions between biomacromolecules. The first fluorescent probe capable of the ratiometric imaging of mitochondrial polarity is reported. The probe, termed BOB, has two absorption maxima (λabs=426 and 561 nm) and two emission maxima—a strong green emission (λem=467 nm) and a weak red emission (642 nm in methanol)—when excited at 405 nm. However, only the green emission is markedly sensitive to polarity changes, thus providing a ratiometric fluorescence response with a good linear relationship in both extensive and narrow ranges of solution polarity. BOB possesses high specificity to mitochondria (Rr=0.96) that is independent of the mitochondrial membrane potential. The mitochondrial polarity in cancer cells was found to be lower than that of normal cells by ratiometric fluorescence imaging with BOB. The difference in mitochondrial polarity might be used to distinguish cancer cells from normal cells. 相似文献
17.
The interaction of Co(Ⅱ) with BSA under UV C (253.7 nm) irradiation under physiological conditions has been studied by UV-vis spectrum, ultraviolet second-derivative spectroscopy and fluorescence spectrum. The quenching rate constant kq and the association constant Ka were calculated according to Stern-Volmer equation based on the quenching of the fluorescence of BSA by Co(Ⅱ). 相似文献
18.
Bis(2-ethylhexyl)phthalate (DEHP) is one of the biggest selling synthetic plasticizers which can migrate to environment and enter human body via air, water, medical apparatus, and food. In this paper, three-dimensional fluorescence (3D-FL) spectroscopy, UV–visible absorption spectroscopy and circular dichroism (CD) spectroscopy were employed to explore the binding of DEHP to bovine serum albumin (BSA) at the physiological conditions. The number of binding sites n and observed binding constant K b was measured by fluorescence quenching method. It was found that the fluorescence quenching was static quenching mechanism and caused by the formation of DEHP–BSA complex at ground state. The enthalpy change (ΔH θ), Gibbs free energy change (ΔG θ) and entropy change (ΔS θ) were calculated at four different temperatures. Site marker competitive displacement experiments were carried out to identify the binding location. The results demonstrated that DEHP bound primarily on Sudlow’s site I in domain IIA of BSA molecule. The distance r (2.95?nm) between donor (BSA) and acceptor (DEHP) was obtained based on F?rster’s non-radiation fluorescence resonance energy transfer (FRET) theory. Furthermore, the CD spectral results indicated that the secondary structure of BSA changed in presence of high concentration of DEHP, which implied that high level of DEHP in plasma was potentially poisonous. The study is helpful to evaluating the health risk of DEHP and understanding its functional effects on protein during the blood transportation process. 相似文献
19.
The interaction between apigenin (Ap) and bovine serum albumin (BSA) in physiological buffer (pH = 7.4) is investigated by
fluorescence quenching technique and UV-vis absorption spectra. The results reveal that Ap could strongly quench the intrinsic
fluorescence of BSA. The quenching mechanism of Ap for BSA varies with the change of Ap concentration. when Ap concentration
is lower, it is a static quenching procedure, when Ap concentration is higher, a combined quenching (both static and dynamic)
would operate. The apparent binding constants Ka and number of binding sites n of Ap with BSA are obtained by fluorescence
quenching method. The thermodynamic parameters, enthalpy change (Δr
H
m
and entropy change (Δr
S
m
), are calculated to be −15.382 kJ mol−1 K−1 < 0 and 104.888 J mol−1 K−1 > 0, respectively, which indicate that the interaction of Ap with BSA is driven mainly by hydrogen bonding and hydrophobic
interactions. The distance r between BSA and Ap is calculated to be 1.89 nm based on F?rster’s non-radiative energy transfer theory. The results of synchronous
fluorescence spectra show that binding of Ap with BSA cannot induce conformational changes in BSA. 相似文献
20.
The interaction between daidzein and 3′-daidzein sulfonic sodium with bovine serum albumin (BSA) in physiological buffer (pH
= 7.4) is investigated by fluorescence quenching technique and UV/vis absorption spectra. The results reveal that both daidzein
and 3′-daidzein sulfonic sodium could strongly quench the intrinsic fluorescence of BSA. The quenching mechanism of both the
daidzein and 3′-daidzein sulfonic sodium for BSA is static quenching procedure. The apparent binding constants K
a and number of binding sites n of daidzein and 3′-daidzein sulfonic sodium with BSA are obtained by fluorescence quenching method. The thermodynamic parameters,
enthalpy change (Δr
H
m
), and entropy change (Δr
S
m
), are calculated, respectively, which indicate that the interaction of daidzein with BSA is driven mainly by hydrogen bonding
and van der Waals, and 3′-daidzein sulfonic sodium with BSA is driven mainly by hydrophobic forces. The distance r between BSA with daidzein and 3′-daidzein sulfonic sodium are calculated to be 4.02 nm and 3.08 nm, respectively, based on
F?rster’s non-radiative energy transfer theory. The results of synchronous fluorescence spectra show that binding of daidzein
and 3′-daidzein sulfonic sodium with BSA cannot induce conformational changes in BSA. 相似文献