| Glucosidase is an important biochemical enzyme group, which can catalyze the hydrolysis of the glycosidic bond in oligosaccharides and polysaccharides, it has a broad application prospects in fields of biochemistry, biomedicine and industry.O-glycosidic bonds and N-glycosidic bonds are ubiquitous in nature, while C-glycosidic bonds is rare and the hydrolysis of C-glycosidic bondsare not as easy as the typical O-glycosidic bonds. In this thesis, the catabolism of pseudouridine-5-phosphate was taken as an example to study the reaction metabolism of hydrolysis of C-glycosides bonds by glycosides. For the transition metal ions, Pd2+was known to be one of the metal ions which can form stable stable complexes with nucleic acid bases. It can be used to distinguish one natural base from the other three.Besides, the interaction of 2,6- two substituted pyridine complexes of Pd2+ with5’-nucleoside phosphate was studied in order to find the relevant rules.Metalloproteinases are a kind of protease whose active center is metal ion, and metalloproteinase inhibitor is becoming a research hotspot. Some studies have found that kojic acid can complex with the metal ions of metalloproteinases in organisms,and it can be used as metal enzyme inhibitors. Nevertheless, the cytotoxicity of kojic acid and its instability during storage aroused people’s research interest of kojic acid derivatives.The coordination properties of Kojic-βAla-Kojic with different metal ions were studied in this thesis. The full paper is divided into five chapters,as followed:In the first chapter, the main theoretical basis and calculation method used in this paper have been summarized. Additionally, it summarizes glucosidase, pseudouridine and Pd2+ interact with nucleic acids and the research status of kojic acid and metal ions.In the second chapter, the reaction mechanism of glycosidase hydrolyzing the C-glycosidic bonds of pseudouridine-5-phosphate by using Density Functional Theory.The structure of transition state and multiple intermediate in the reaction process were obtained by calculating. The variety in the reaction of each point’s the main geometric parameters such as bond lengths, bond angles and charge have been analyzed. Then the energy barrier value of each step reaction and imaginary frequency of each transition statewere obtained. And finally, the most reasonable reaction path of the whole process was determined.In the third chapter, the interaction of pyridine-2,6-dicarboxamide(Ⅰ) 、N7,N8-diisopropyl derivatives(Ⅱ) complexes of Pd2+ with four nucleoside5’-monophosphates were studied in the singlet and triplet. After analyzing the configuration, charge and frontier molecular orbital of complexes, the results indicated that the interaction of four nucleoside 5’-monophosphates with compound Ⅰ and Ⅱ in the triplet state. The structure of CMP-Ⅰ and AMP(N6’)-Ⅱ were the most stable, the most steady structures were GMP(N6’)-Ⅰ and GMP(N6’)-Ⅱ in the singlet state. In addition, compound Ⅰ is more easily coordinate with nucleoside 5’-monophosphates and the isopropyl of compound Ⅱ has a certain impact on the coordination ability of5’- phosphate and Pd2+. When compound Ⅰ combines with GMP and AMP, it is easier to coordinate with N6’, the situation was similar to compound Ⅱ.In the fourth chapter, the coordination condition of Kojic-βAla-Kojic with different metal ions has been studied. After calculating and analyzing the configuration,charge and frontier molecular orbital of complexes, the results indicated that Zn2+ and Al3+ prefer to form dinuclear complexes and Cu2+ tends to form mononuclear complexes with Kojic-βAla-Kojic. In the formation of complexes, both Al3+ and Cu2+are more likely to coordinate with the oxygen on the B ring. Kojic-βAla-Kojic has the the greatest affinity with Cu2+.In the fifth chapter, the conclusions of the study have been summarized.Besides,the outlooks and plans about the further research are expounded and prospected. |
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