Studies On The Mechanism And Activity Of Small Molecular Structure Analogues And Proteins

As the most important biological macromolecule in the cell,protein has the biological function of carrying and storage.Studying the interaction between small molecule drugs and proteins at the molecular level has always been a hot spot in many fields,such as life sciences,medicinal chemistry and chemistry et.The biological function of a protein is closely related to its complex specific structure.When small molecule acts on protein,the structure of protein will change to a certain extent,which will affect its physiological function.Studying the interaction of small drug molecules with targeted proteins at the molecular level helps to understand the pharmacological behavior of small molecules and proteins,provides a theoretical basis for the screening of small molecules that specifically bind to proteins,and the development and design of new drugs.In this thesis,Isothermal titration calorimetry(ITC),spectroscopy,and molecular simulation docking techniques were used to study the interactions between tectoridin,kaempferide,12 dihydropyrroliazine 1-one derivatives and FTO protein(fat mass and fat-associated),Trypsin(Try),Catalase(CAT),Pepsin(Pep)and Human Serum Albumin(HSA).Related studies have shown that the overexpression of FTO gene can enhance the cell transformation mediated by leukemia oncogenes and the occurrence of leukemia,The CCK8 method was further used to detect the activity inhibitory effect of 12 kinds of dihydropyrrolizin-1-one derivatives(the solubility of tectoridin and kaempferide is not suitable for cell activity experiments)on leukemia cells(K562 cells,HL-60 cells).The content of the thesis is divided into five parts.The first chapter summarizes the structure and function of the protein,as well as the methods and contents of studying the interaction between the protein and small molecules,and briefly describes the CCK8 method to detect the inhibitory activity of small molecules on leukemia cells.In the second chapter,in order to study whether the interaction between FTO protein and tectoridin is specific,FTO protein,CAT,Pep,Try and HSA were selected by ITC from five proteins(FTO,CAT,Pep,Try and HSA).The results showed that,except Try,the other four proteins all had the interaction with tectoridin.In order to further verify the binding ability of the four proteins,the spectroscopic techniques and molecular models were used respectively.The results of fluorescence spectra and data analysis showed that tectoridin bound with four proteins were all the static quenching mechanism.From the experimental data of ITC and the calculation results of fluorescence data,it can be seen that the combination between the four proteins and tectoridin is an exothermic reaction,and hydrogen bond and electrostatic force play an important role in the combination.In addition,by comparing the binding constants of the four proteins and tectoridin at room temperature,it is shown that the binding capacity of the four reaction systems is in sequence: HSA>CAT>Pep>FTO.In chapter three,we studied the interaction mechanism between kaempferide and four proteins by means of spectroscopy and molecular docking technique.It is concluded that the mechanism of action between kaempferide and four proteins is the static quenching mechanism.According to the thermodynamic parameters,the action between kaempferide and the four proteins were mainly hydrophobic,and the four systems were all spontaneous reactions driven by entropy.There was also nonradiative transfer in the interactions between small molecules and the four proteins.By comparing the binding constants and other experimental parameters of the four proteins,it can be obtained that the order of the binding capacity of the four proteins from large to small is: HSA>FTO>Pep>Try.In chapter four,the interaction between 12 derivatives of dihydropyrroliazine 1-one and FTO was studied by means of spectroscopy and molecular docking technology.The interactions of 12 derivatives and FTO were determined by static quenching mechanism.Many of the small molecules binding with FTO were hydrophobic.There was still electrostatic force in the interaction between 1c and FTO,while the type of interaction between 1i and FTO is van der Waals force and hydrogen bond force.Of the 12 derivatives,the strongest FTO binding capacity is 1c.According to relevant studies,FTO gene exists in leukemia cells,so CCK8 method was used to study the toxicity test of 12 derivatives and two types of leukemia cells(K562 cell and HL-60 cell).It was concluded that compounds 1j,1i,1g,1k and 1b had better inhibitory effects on the proliferation of K562 cells.Compounds 1j,1l and 1c had better inhibitory effects on the proliferation of hl-60 cells.In chapters five,we studied the interaction between 12 dihydropyrroliazine 1-one derivatives and three proteins(HSA,Pep,Try)by using spectroscopy and molecular docking techniques.The interactions between 12 derivatives and three proteins were static quenching mechanism.Among the 12 derivatives,1k with HSA(1i with Pep,and 1c with Try)had the strongest binding ability.According to the relevant thermodynamic parameters,the reactions between the 12 derivatives and the three proteins are all entropy-driven spontaneous reactions.The main acting force was hydrophobic,and hydrogen bonding was also used in some systems.