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ABSTRACT: The interaction of 5-spiro-3'-piperidine-2″-spiro-3″-indole-4',2″-diones (SPSDs), an anti-tumor drug, to bovine serum albumin (BSA) in aqueous solution has been investigated by fluorescence spectra and ultraviolet-visible (UV-vis) spectra at pH 7.40. We have studied the effect of four substituents on the SPSD for the first time. The results of fluorescence titration indicated that SPSD can quench the intrinsic fluorescence of BSA and the quenching mechanism has been analyzed. The binding sites number (n), the binding constant (K(A)) and the spatial-distance (r) of SPSD with BSA without or with substituents on the benzene ring at 302 and 310K have been calculated. The results show that the presence of the substituents increased the binding constant and changed the binding distance between the acceptor and the donor, which possibly results from the formation of SPSD-BSA complex. We have investigated the possible sub-domain on BSA where bind SPSD by displacement experiments. The effect of SPSD on the conformation of BSA has also been analyzed using synchronous fluorescence under experimental conditions.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 12/2012; 104C:519-526. · 2.10 Impact Factor
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ABSTRACT: The fluorescence and ultraviolet spectroscopy were explored to study the interaction between Oxymetazoline hydrochloride (OMZH) and mucin under imitated physiological condition. The results demonstrated that the fluorescence quenching mechanism between OMZH and mucin is a combined quenching process. The binding constants (K(a)), binding sites (n) and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) of the interaction system were calculated at different temperatures. The hydrogen bonds and van der Waals forces play a major role in the interaction between OMZH and mucin. According to Förster non-radiation energy transfer theory, the binding distance between OMZH and mucin was calculated.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 11/2012; 103C:125-129. · 2.10 Impact Factor
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ABSTRACT: The intermolecular interaction between N-confused porphyrins-(3-methylisoxazole) diad (NCP-(3-methylisoxazole)) and bovine serum albumin (BSA) has been investigated through fluorescence and ultraviolet spectroscopy at different temperatures under imitated physiological conditions. The results showed that the fluorescence of BSA was quenched by NCP-(3-methylisoxazole) through a combined quenching procedure. The characteristics of NCP-(3-methylisoxazole)⋯BSA interaction (including interaction nature, interaction conformation, binding constants, binding sites, binding distance, thermodynamic parameters, etc.) and the effect of metal ions (Cu(2+), Mg(2+), Ca(2+), and Ni(2+)) upon the NCP-(3-methylisoxazole)⋯BSA interaction have been detailed studied.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 09/2012; 99C:116-121. · 2.10 Impact Factor
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ABSTRACT: The interaction between 3-spiro-2'-pyrrolidine-3'-spiro-3″-piperidine-2,3″-dione (PPD) and bovine serum albumin (BSA) in aqueous solution was studied using fluorescence and UV-vis spectroscopy. Fluorescence emission data revealed that BSA (1.00 × 10(-5) mol/L) fluorescence was statically quenched by PPD at various concentrations, which implies that a PPD-BSA complex was formed. The binding constant (K(A) ), the number of binding sites (n) and the specific binding site of the PPD with BSA were determined. Energy-transfer efficiency parameters were determined and the mechanism of the interaction discussed. The thermodynamic parameters, ΔG, ΔH and ΔS, were obtained according to van't Hoff's equation, showing the involvement of hydrophobic forces in these interactions. The effect of PPD acting on the BSA conformation was detected by synchronous fluorescence. Copyright © 2012 John Wiley & Sons, Ltd.
Luminescence 09/2012; · 1.73 Impact Factor
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ABSTRACT: The interaction between thiazolo[2,3-b]pyrimidine (TZPM) analogues and bovine serum albumin (BSA) was investigated by fluorescence spectroscopy and UV-Vis spectroscopy at two different temperatures (299 and 307K) under imitated physiological conditions. The results indicate that both static quenching and dynamic quenching contribute to the fluorescence quenching of BSA by TZPM. The binding constant (K(a)) and binding sites (n) were calculated from the obtained spectra. Based on the Förster non-radiation energy transfer theory, the average binding distance between BSA and TZPM was estimated. The synchronous fluorescence spectra indicate that the conformation of BSA has been changed. The comparison of binding potency of TZPM and BSA suggests that the substituents on the benzene ring enhance the binding affinity of TZPM and BSA. We investigated the possible sub-domains on BSA that bind TZPM by displacement experiments. Furthermore, to explore the effect of molecular structure on the binding, a study on quantitative structure-property relationship (QSPR) was performed, the quantitative relationship equation of R(0), r and K(a) were obtained. We observed that R(0), r and K(a) between BSA and TZPM is connected with the margin of the highest and the lowest occupied orbital energy (ΔE), dipole moment (μ), Molar Volume (V(m)), Mole Mass (M).
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 07/2012; 96:690-7. · 2.10 Impact Factor
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ABSTRACT: Both lomefloxacin (LOM) and ofloxacin (OFL) have a powerful ability to quench the fluorescence of bovine serum albumin (BSA).
The fluorescence quenching action is much stronger when the two drugs coexist. The synergism between LOM and OFL was studied
using fluorescence and ultraviolet spectroscopy under imitated physiological conditions. The results show that static quenching
and non-radiation energy transfer are the main reasons for the fluorescence quenching. The synergism results in both the reduction
of the binding stability between drugs and BSA and an increase of the free drug concentration, which will increase the efficacy
of drugs. The thermodynamic parameters at different temperatures were calculated and the binding distances r between the drugs and BSA were obtained based on Försters theory of non-radiation energy transfer. The synchronous fluorescence
spectra indicated that the effect of synergism affected the conformation of BSA.
KeywordsFluorescence spectrum–Bovine serum albumin–Synergism–Lomefloxacin–Ofloxacin
Journal of Solution Chemistry 04/2012; 40(3):521-531. · 1.41 Impact Factor
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ABSTRACT: Spiro pyrrolidines, which were proved with diverse and potent biological activities and they were discovered widespread in nature. In this paper, using fluorescence and ultraviolet spectroscopy, we investigated the interactions between novel spiro pyrrolidine (NSP) and bovine serum albumin (BSA) under the imitated physiological condition. The results show that the NSP binds to BSA molecules. Static quenching and non-radiation energy transfer are the main reasons for fluorescence quenching. We calculated the binding constant (K(a)) and binding sites (n) at different temperatures and obtained the binding distance between the tryptophan residue in BSA and the NSP based on the Förster theory of non-radiation energy transfer. In addition, using synchronous fluorescence spectra, we demonstrated conformation changes of BSA caused by NSP. The comparison of binding potency of NSP and BSA suggests that the substituent on the benzene ring influences the binding ability of NSP and BSA.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 03/2012; 94:23-9. · 2.10 Impact Factor
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ABSTRACT: The 1,3-dipolar cycloaddition reaction of 2-methyl-N-confused porphyrin with 2,6-dichlorobenzonitrile oxide yielded four isomeric monoadducts of carbachlorin type and one diadduct of carbabacteriochlorin type. Two major carbachlorin products, constituting 82% of the monoadducts, were shown to be structural precursors of the unique 2-aza-21-carbabacteriochlorin. Enantiomers of the most abundant isomer of 2-aza-21-carbachlorin (55% of all carbachlorin products) have been resolved. The crystal structures of 2-aza-21-carbabacteriochlorin and the most abundant isomer of 2-aza-21-carbachlorin were characterized by X-ray diffraction.
The Journal of Organic Chemistry 03/2012; 77(5):2431-40. · 4.45 Impact Factor
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ABSTRACT: The interaction between N-confused porphyrins-(4-hydroxycoumarins) diad (NCP-(4-hydroxycoumarins)) and bovine serum albumin (BSA) was studied using fluorescence and ultraviolet spectroscopy at different temperatures under imitated physiological conditions. The experimental results showed that the fluorescence of BSA was quenched by NCP-(4-hydroxycoumarins) through a combined quenching procedure. The binding constants, binding sites and corresponding thermodynamic parameters between NCP-(4-hydroxycoumarins) and BSA at different temperatures were obtained. According to Förster non-radiation energy transfer theory, the binding distance between BSA and NCP-(4-hydroxycoumarins) was calculated to be about 2.1 nm. The effect of NCP-(4-hydroxycoumarins) on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy. In addition, the effect of some metal ions Cu(2+), Ca(2+), Mg(2+), and Ni(2+) on the binding constant between NCP-(4-hydroxycoumarins) and BSA was examined.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 02/2012; 91:113-7. · 2.10 Impact Factor
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ABSTRACT: The fluorescence and ultraviolet spectroscopies were explored to study the interaction between N-confused porphyrins-edaravone diad (NCP-EDA) and bovine serum albumin (BSA) under simulative physiological condition at different temperatures. The experimental results show that the fluorescence quenching mechanism between NCP-EDA and BSA is a combined quenching (dynamic and static quenching). The binding constants, binding sites and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) of the interaction system were calculated at different temperatures. According to Förster non-radiation energy transfer theory, the binding distance between NCP-EDA and BSA was calculated to be 3.63 nm. In addition, the effect of NCP-EDA on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 09/2011; 83(1):609-13. · 2.10 Impact Factor
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ABSTRACT: The interaction between imidazo[2,1-b]thiazole (IMTZ) and bovine serum albumin (BSA) was analyzed by fluorescence and ultraviolet spectroscopy at 302 and 310 K under simulative physiological conditions. The results show that IMTZ can effectively quench the intrinsic fluorescence of BSA via static and dynamic quenching. The binding constant, binding sites of IMTZ with BSA were calculated. According to the Förster non-radiation energy transfer theory, the average binding distance between IMTZ and BSA was obtained. What's more, the synchronous fluorescence spectra indicated that the conformation of BSA has been changed. The results provided the information for the binding of IMTZ to BSA, and the influences of substituent group on the interaction were also discussed.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 08/2011; 83(1):322-8. · 2.10 Impact Factor
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ABSTRACT: Novel photoswitchable fluorescent nanoparticles were fabricated by a facile one-step mini-emulsion polymerization, in which fluorescence resonance energy transfer (FRET) donor, 9,10-diphenylanthracene (DPA), and photoswitchable acceptor, spiropyran derivate, were simultaneously embedded in polymer matrix during the polymerization process. The prepared fluorescent nanoparticles exhibit the typical absorption properties of both DPA dye and spiropyran moiety, indicating that the two chromophores have been incorporated into the polymer nanoparticles. The obtained fluorescent nanoparticles exhibited superior photoswitchable fluorescent performance due to the effective photoinduced interparticle FRET. Moreover, the novel photoswitchable fluorescent nanoparticles also revealed small size (ca. 60 nm), high intensity, relatively fast photoresponsive property and good photoreversibility in aqueous media.
Journal of Macromolecular Science Part A 08/2011; Part A(Vol. 48):637-643. · 0.89 Impact Factor
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ABSTRACT: Fluorescence and ultraviolet spectroscopy were used to explore the interaction between thiazolopyrimidines (TAPM) and bovine serum albumin (BSA) under imitated physiological conditions. The experimental results show that thiazolopyrimidines can quench the fluorescence of BSA through a static quenching process. The binding constants, binding sites, and thermodynamic parameters at different temperatures were calculated. The calculated results indicate that the interaction between thiazolopyrimidines and BSA is driven mainly by Van der Waals' force and hydrogen bonds. The binding distances r was obtained based on Förster theory of non-radiation energy transfer. The comparison of binding potency of thiazolopyrimidines and BSA suggests that the substituent on the benzene ring promotes the binding process of thiazolopyrimidines and BSA.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 06/2011; 79(5):1931-5. · 2.10 Impact Factor
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ABSTRACT: In the present study, novel polymeric nanoparticles of ca. 55 nm in diameter with reversibly photoswitchable fluorescence properties were synthesized using a facile one-step miniemulsion polymerization, in which the donor of fluorescence resonance energy transfer (FRET), 4-methamino-9-allyl-1,8-naphthalimide (MANI), and the acceptor, spiropyran-linked methacrylate (SPMA), were covalently incorporated into a polymeric matrix during the polymerization process. The fluorescence emission of MANI dye in nanoparticles can be reversibly switched using the alternating irradiation of UV and visible light, which can induce the structural interconversion between the SP form and MC form of spiropyran moieties inside nanoparticles and thus reversibly switch on and switch off the FRET process. The prepared photoswitchable fluorescent polymer nanoparticles not only show a high load capacity of dyes, controllable amount and ratio of the two dyes, and tunable FRET efficiency but also exhibit higher spectral stability because of covalent linkage between dye molecules and the particle, relatively fast photoresponsibility, and better photoreversibility compared to some previously reported systems.
The Journal of Physical Chemistry B 03/2011; 115(13):3354-62. · 3.70 Impact Factor
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Chinese Journal of Chemistry 02/2011; 29(1):97 - 101. · 0.75 Impact Factor
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ABSTRACT: Active methylene compounds such as 5,5-dimethylcyclohexane-1,3-dione, cyclohexane-1,3-dione, 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one, 1,3-dimethyl-1H-pyrazol-5(4H)-one, and 3-methylisoxazol-5(4H)-one react with the 3-C position of N-confused porphyrin in THF for 5 min to afford a novel type of N-confused porphyrin derivatives in good yield without the need of any catalyst.
The Journal of Organic Chemistry 02/2011; 76(7):2345-9. · 4.45 Impact Factor
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ABSTRACT: The interaction between salvianic acid A sodium (SAS) and bovine serum albumin (BSA) was investigated using fluorescence and ultraviolet spectroscopy at different temperatures under imitated physiological conditions. The experimental results showed that the fluorescence of BSA was quenched by SAS through a static quenching procedure. The binding constants of SAS with BSA were 2.03, 1.17 and 0.71×10(5) L mol(-1) at 291, 298 and 305 K, respectively. Negative values of ΔG, ΔH, and ΔS indicate that the interaction between SAS and BSA is driven by hydrogen bonds and van der Waals forces. According to Förster non-radiation energy transfer theory, the binding distance between BSA and SAS was calculated to be about 2.92 nm. The effect of SAS on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy. In addition, the effect of some metal ions Cu(2+), Ca(2+), Mg(2+), and Zn(2+) on the binding constant between SAS and BSA was examined.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 02/2011; 78(5):1535-9. · 2.10 Impact Factor
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ABSTRACT: The fluorescence and ultraviolet spectroscopy were explored to study the interaction between N-confused porphyrins (NCP) and bovine serum albumin (BSA) under imitated physiological condition. The experimental results indicated that the fluorescence quenching mechanism between BSA and NCP was static quenching procedure at low NCP concentration at 293 and 305 K or a combined quenching (static and dynamic) procedure at higher NCP concentration at 305 K. The binding constants, binding sites and the corresponding thermodynamic parameters ΔH, ΔS, and ΔG were calculated at different temperatures. The comparison of binding potency of the three NCP to BSA showed that the substituting groups in benzene ring could enhance the binding affinity. From the thermodynamic parameters, we concluded that the action force was mainly hydrophobic interaction. The binding distances between NCP and BSA were calculated using Förster non-radiation energy transfer theory. In addition, the effect of NCP on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 01/2011; 78(4):1329-35. · 2.10 Impact Factor
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ABSTRACT: To understand the effects of benzimidazole substitution on reaction equilibrium, the interactions between a series of benzimidazole-like ligands and [OV(O₂)₂(D₂O)]⁻/[OV(O₂)₂(HOD)]⁻ in solution were explored by a combination of multinuclear ((1)H, (13)C, and (51)V) magnetic resonance and variable temperature NMR in 0.15 mol/L NaCl ionic medium for mimicking the physiological condition. Some direct NMR data are reported for the first time. These results show that the relative reactivity among the organic ligands is 2-methyl-1H-benzo[d]imidazole>(1H-benzo[d]imidazol-2-yl)methanol>1-(1H-benzo[d]imidazol-2-yl)ethanol>1H-benzo[d][1,2,3]triazole. Both the steric effect and the electron effect of the 2-position substituted groups in benzimidazole ring affect the reaction equilibrium. The competitive coordination results in the formation of a series of new six-coordinated peroxovanadate species [OV(O₂)₂L]⁻(L=benzimidazole-like ligands). Moreover, the results of density functional calculations provided a reasonable explanation on the relative reactivity of the benzimidazole-like ligands as well as the important role of solvation in these reactions.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 11/2010; 77(4):816-20. · 2.10 Impact Factor
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ABSTRACT: The interaction between diperoxovanadate complexes (K₃)[VO(O₂)₂(C₂O₄)]·H₂O and [VO(O₂)₂(D₂O)](-)/[VO(O₂)₂(HOD)](-)) and glycyl-histidine (abbr. GlyHis) in solution was studied by 1D NMR including variable-temperature NMR, 2D diffusion ordered spectroscopy (DOSY), HMQC and density functional theory (DFT) calculations. The results indicate that a pair of [VO(O₂)₂(GlyHis)](-) isomers is formed. The vanadium in the new species is coordinated by either the ɛ-N or δ-N in the imidazole ring. The relative ratio of the isomers was affected by temperature. Theoretical calculation results provide a reasonable explanation on the relative coordination capability of different nitrogen sites. Solvation effect is shown to be important for the reactivity of the interaction system.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 11/2010; 77(4):825-31. · 2.10 Impact Factor
