The Study Of Non-enzymatic Cleavage Of Oligodeoxyribonucletide By Cerium Complex At Specific Site

Synthesis of the artificial endo-enzyme that can hydrolyze the DNA strand at specific site quickly in physiological condition is a hot research direction. Many theses published have demonstrated that metal ions and its complex can hydrolyze the phosphor diester of nucleic acids, but these research is just in a primary stage. There are many secretes still in dark to be exposed by us. In this thesis, we systematically studied the absorption state change of the oligodeoxynucleotides (ODN) on the silver electrode surface and the specific hydrolysis of the ODN by the artificial endo-enzyme.For the reason that many biochemical reactions occurred on the charged surface of the membrane, it is necessary to study the absorption state of the ODN on these interfaces. Here we first study the surface enhanced Raman spectrum of 13-mers ODN and 26-mers ODN on silver electrode, and then we study the influence of the potential to the adsorption state of the ODN on the silver electrode. By using the surface enhanced Raman spectrum, we got the information of the ODN about how they adsorption on the electrode and how they chage their adsorption state. We also study the difference of Raman spectra between the ODNs.The artificial endo-enzyme we devised contains two parts. One is called recognition factor and the other is called scissor. To cleave DNA specifically, we first make the artificial endo-enzyme to recognize the substrate and combine firmly with it. The recognition factor of the artificial endo-enzyme we designed has the same base sequence with the substrate DNA. For studying the reaction between the endo-enzyme and the substrate, we inspect the fluorescence spectrum of this reaction by using ion fluorescence probe. And this method has many merits such as high sensitivity, manageability and etc.. The experiment results show that the compound synthesized for cleaving DNA specifically can combine with the substrate DNA very especially and firmly.On the basis of those research, we study the formation of tri-helix DNA by using the fluorescence ion probe. Tri-helix DNA is the core of the antisense and antigene technology. It control the expression and suppression of gene. Our experiment results show that Tb3+ can detect the formation of tri-helix DNA. And we also study the fluorescence spectra of Tb3+ after it reacts with different kinds of tri-helix DNA. And the influences of pH and metal ions to the formation oftri-helix DNA are also discussed.After those research work, EDTA hydride were attached covalently to the 5' phosphorous terminus of the 10-mers ODN via an ethylenediamine linkage to prepare a sequence-recognizing moiety. Then sequence-specific cleavage of 26-mers ODN was studied by Ce4+complex compound with sequence recognizing moiety. The experiment results demonstrate that the artificial endo-enzyme can hydrolysis the DNA with sequence specificity and the mechanism of this cleavage reaction is also studied.Besides these, HXTA-2Ce complex is synthesized and the cleavage reaction of helix DNA by the binuclear complex is also researched. Micelle is a kind of ideal simulation device of cells. We discuss the hydrolysis reaction of DNA by Ce4+ in micelle.