Preliminary Study On DNA Interaction And Elimination Mechanism Of Anthracene And Benzo[a]pyrene In Vitro

In this paper,anthracene（ANT）and benzo[a]pyrene（Ba P）were selected as the research objects.Through a variety of analysis methods,the interaction mode and intensity between them and DNA in vitro were investigated,as well as the effects of different environmental factors on the interaction between Ba P and DNA in vitro,so as to established a method of selective capture and elimination of Ba P by DNA.The specific experimental results were as follows:（1）The results of UV-vis spectra showed that ANT and Ba P formed new complexes with DNA,respectively.The results of DNA melting point determination showed that the intercalation of ANT and Ba P into DNA could promote the stability of the DNA double helix structure,and the thermal melting temperature of DNA increased by 9.9℃and12.7℃,respectively.In circular dichroism spectra experiments,the two CD signal peaks of DNA were changed,which indicated that the interaction between DNA bases was destroyed by the intercalation of ANT and Ba P.In the fluorescence spectra experiment,DNA could effectively quench the fluorescence intensity of ANT and Ba P.In the experiment of fluorescence microscope observation,EB was used as the control group.The results showed that ANT,Ba P and EB had the ability to intercalate with DNA.These results indicated that the binding mode of ANT and Ba P with DNA in vitro was intercalation.The results of combined with kinetic analysis showed that the quenching mode of interaction between ANT and Ba P with DNA were combined quenching process of dynamic and static and static quenching,respectively.Thermodynamic data showed that van der Waals forces and hydrogen bonds were the main driving forces of the bonding process,and they were spontaneous.At room temperature,the DNA binding saturation values of them were 0.76 and 1.18,respectively,and the ability of Ba P to intercalate with DNA was better.（2）The optimum temperature and p H of Ba P interaction with DNA were 35℃and p H 7.40,respectively,and the DNA binding saturation value was 1.41.Under the optimal conditions,the addition of NaCl made the DNA binding saturation value of Ba P-DNA system decreased,while the other factors（CaCl₂,sodium dodecyl sulfonate,glucose,vitamin C,urea,lysine and leucine）increased the DNA binding saturation value,which indicated that them were beneficial to the interaction between Ba P and DNA in vitro.（3）The results of capturing and eliminating of Ba P by DNA showed that when the amount of DNA was 0.78×10^-3 mg,the removal rate of Ba P at the initial concentration of5.63×10^-5 mol/L was 97.66%.The presence of NaCl in the system reduced the removal rate of Ba P,and other factors（CaCl₂,sodium dodecyl sulfonate,glucose,vitamin C,urea,lysine,leucine）all increased the removal rate of Ba P.The magnetic beads had good reusability in this experiment.The above results showed that the binding mode of ANT and Ba P with DNA in vitro was intercalation,and Ba P had a stronger ability to intercalate with DNA than ANT.By changing the reaction conditions and adding a variety of environmental factors that were conducive to the intercalation of Ba P into DNA,the removal rate of Ba P was improved,which provided a novel insight for the capture and elimination of PAHs in the environment through PAHs-DNA intercalation.