Studies On The Interaction Between Small Molecule Compounds And DNA By Spectral Methods

Along with the widely uses of feed additive, veterinary medicine, pesticide, andso on, the issue of food safety has increasingly become the focus of attention. Theresidues of above substances in food may creat a potential risk to the the health ofconsumers. The molecular weight of such substances is less than1000; they belong tosmall molecule compounds. The small molecule compounds may interact with DNAdirectly or indirectly in vivo, which may change DNA structure and induce oxidativedamage to DNA, and then affect its function or genetic characteristic. Based on thisconsideration, study of the mode and mechanism of interaction between smallmolecule compounds with DNA is with realistic significance. It may be usefullyapplied to researching the impact of extracorporeal compounds on the structure andfunction of DNA, mechanism of toxicity and eliminating the adverse reactions. Themain contents and the results of this paper are as following:(1) The interaction of salbutamol sulphate (SS) with herring sperm DNA(hsDNA)in the pH7.4Tris-HCl buffer solution reaction system was investigated by means ofUV-Vis absorption spectra, fluorescence spectra, denaturation of DNA, salt effect,viscometry thermal, and so on. The experimental results from UV-Vis absorptionspectra show that when hsDNA was added, the red-shift and hyperchromic effectwere observed in the absorption peak of SS, which indicate that SS interacted withhsDNA might not be classic intercalation binding mode. The experimental resultsfrom denaturation of DNA show that when SS was added, the differences ofdenaturation temperature are not significant, which indicate that SS interacted withhsDNA might be in electrostatic interaction or groove binding mode. Theexperimental results from salt effect, KI fluorescence quenching experiment andviscometry thermal show that SS interacted with hsDNA in electrostatic interactionand groove binding mode. The fluorescence quenching model between SS andhsDNA belonged to static fluorescence quenching. The binding constant for SS withhsDNA was K=1.51×104L·mol-1, and the number of binding sites was n=1.27.(2) The interaction of terbutaline sulfate (TS) with hsDNA in the pH7.4Tris-HClbuffer solution reaction system was investigated by means of UV-Vis absorptionspectra, fluorescence spectra, salt effect, viscometry thermal, DNA activityexperiment, and so on. The experimental results from UV-Vis absorption spectra show that when hsDNA was added, the red-shift and hyperchromic effect were observed inthe absorption peak of TS, which indicate that TS interacted with hsDNA might not beclassic intercalation binding mode. The experimental results from DNA activityexperiment and KI fluorescence quenching experiment show that TS interacted withhsDNA might not be in single intercalation or groove binding mode but might be inelectrostatic interaction mode only or electrostatic interaction and groove bindingmode simultaneously. The experimental results from salt effect and viscometrythermal show that TS interacted with hsDNA in electrostatic interaction and groovebinding mode. The fluorescence quenching model between TS and hsDNA belongedto static fluorescence quenching. The binding constant for TS with hsDNA wasK=2.95×103L·mol-1, and the number of binding sites was n=0.92.(3) Using methylene blue as the probe molecule, the interaction ofglufosinate-ammonium (GA) with hsDNA was investigated by means of UV-Visabsorption spectra, fluorescence spectra, denaturation of DNA, viscometry thermal,DNA activity experiment, and so on. The experimental results from UV-Visabsorption spectra, denaturation of DNA and viscometry thermal show that GAinteracted with hsDNA might be in intercalation binding mode. The experimentalresults from DNA activity experiment show that GA interacted with hsDNA not onlymight be in single intercalation binding mode, but also might be in electrostaticinteraction mode or groove binding mode. The experimental results from salt effectshow that GA interacted with hsDNA in electrostatic interaction mode. Theexperimental results from fluorescence spectra show that the fluorescence quenchingmodel between GA and hsDNA was not belonged to single static fluorescencequenching or single dynamic fluorescence quenching, but belonged to the doublefluorescence quenching of mixed. The binding constant for GA with hsDNA wasK=2.12×105L·mol-1, and the number of binding sites was n=2.9.The experiments show that the interaction of different small moleculecompounds with DNA is different. According to the mechanism of interactionbetween them, using different methods to eliminate these interactions, which will helppeople live longer and healthier lives.