| In this study,the interactions between small molecular drugs and DNA,serum album were investigated by spectrometric methods and molecular docking.The main points were as below:Cryptotanshinone interacting with human serum albumin(HSA)was investigated under pH=7.40 by multi-spectroscopic methods.Cryptotanshinone quenched the intrinsic fluorescence of HSA via a static quenching procedure.The values of the binding constant and the numbers of binding sites were calculated at different temperatures.According to the thermodynamic parameters,electrostatic force might be main acting force between cryptotanshinone and HSA.The site marker competitive studies indicated that cryptotanshinone was binding at site I on HSA.The results of synchronous fluorescence spectra and circular dichroism(CD)spectra showed cryptotanshinone changed secondary structure of HSA.The effects of metal ions on cryptotanshinone binding to HSA were studied.The binding distance between cryptotanshinone to HSA was determined as 2.86 nm according to the F?rster energy tansference.The interaction between salmeterol xinafoate and bovine serum albumin(BSA)was studied by spectrometric methods and molecular docking.The UV spectra of salmeterol xinafoate were changed after adding BSA.The results of fluorescence quenching and the time-resolved fluorescence spectroscopy showed that the salmeterol xinafoate quenching BSA was a static process.The values of the binding constant and the numbers of binding sites were calculated at different temperature.According to the thermodynamic parameters,electrostatic force might be main acting force between salmeterol xinafoate and BSA.The site marker competitive studies indicated that salmeterol xinafoate was binding at site I on BSA.The results of Fourier transform infrared(FT-IR)spectroscopy,synchronous fluorescence spectra and CD spectra showed that the addition of the salmeterol xinafoate had an effect on the secondary structure of BSA.The effects of metal ions on salmeterol xinafoate binding to BSA were studied.The result of molecular docking was consistent with above experiments.The binding distance between salmeterol xinafoate to BSA was determined as 2.37 nmThe interaction between dextromethorphan hydrobromide and DNA in Tris-HCl buffer solution(pH 7.40)was investigated by various spectroscopic techniques,viscosity measurements,voltammetric studies and molecular docking.Both the Stern-Volmer plots at different temperatures and the time-resolved fluorescence spectroscopy suggested that the DNA quenching dextromethorphan hydrobromide was static.The binding constants and the number of binding sites between dextromethorphan hydrobromide and DNA at 291,301 and 311 K were calculated.The values of ?H,?S and ?G suggested that van der Waals force or hydrogen bond might be main acting force between dextromethorphan hydrobromide and DNA.The binding distance was 2.54 nm.The results of FT-IR measurement and CD spectroscopy indicated that the addition of the dextromethorphan hydrobromide had an effect on the secondary structure of DNA.The binding mode of dextromethorphan hydrobromide and DNA was intercalative binding by UV spectroscopy,the effect of ionic strength,viscosity measurements,DNA melting studies and the interaction of dextromethorphan hydrobromide and single stranded DNA(ssDNA).The results of voltammetric studies indicated the peak potential of dextromethorphan hydrobromide was changed after adding DNA.And the result of molecular docking further indicated that the chromophore of dextromethorphan hydrobromide could slide into the G-C rich region of DNA and the interaction between dextromethorphan hydrobromide and DNA was intercalation and hydrogen bond played an important role.The binding of neomycin sulphate/paromomycin sulfate with DNA was investigated by fluorescence quenching using acridine orange(AO)as a fluorescence probe.The results of Stern-Volmer plots and time-resolved fluorescence spectroscopy all revealed that neomycin sulphate/paromomycin sulfate quenching the fluorescence of AO-DNA was static in nature.The binding constant of neomycin sulphate/paromomycin sulfate and AO-DNA was 6.70 × 103/1.44 × 103 L·mol-1 at 291 K.The values of ?H,?S and ?G suggested that van der Waals force or hydrogen bond might be the main binding force between neomycin sulphate/paromomycin sulfate and DNA.The results of FT-IR measurement and CD spectroscopy indicated that the addition of the neomycin sulphate/paromomycin sulfate had an effect on the secondary structure of DNA.The binding mode between neomycin sulphate/paromomycin sulfate and DNA was groove binding by the effect of ionic strength,viscosity measurements,DNA melting studies and the interaction of neomycin sulphate/paromomycin sulfate and ssDNA.The results of molecular docking further indicated that neomycin sulphate/paromomycin sulfate could enter into the minor groove in the A-T rich region of DNA.The binding of micronomicin and tobramycin with DNA was investigated using ethidium bromide(EB)as a fluorescence probe by spectroscopic methods,relative viscosity and molecular docking.The results of fluorescence quenching and time-resolved fluorescence spectroscopy all revealed that micronomicin/tobramycin quenching the fluorescence of EB-DNA was static.The binding constant of micronomicin/tobramycin and EB-DNA was calculated.The values of ?H,?S and ?G suggested that van der Waals force or hydrogen bond might be the main binding force between micronomicin/tobramycin and DNA.The results of FT-IR measurement and CD spectroscopy indicated that the addition of the micronomicin/tobramycin had an effect on the secondary structure of DNA.The binding mode between micronomicin/tobramycin and DNA was groove binding by the effect of ionic strength,viscosity measurements,DNA melting studies and the interaction of micronomicin/tobramycin and ssDNA.The result of molecular docking indicated the binding mode was groove binding and the hydrogen bond played an important role in the binding process,which were consistent with other experiments. |
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