Spectroscopy Investigation Of The Interaction Of FTO Proteins With Small Molecule Drugs And Analogs

FTO gene is highly expressed in the hypothalamus, skeletal muscle, fat and other huaman tissues. It may inhibit the metabolism and reduce energy consumption efficiency, and thus lead to obesity. The FTO gene product, FTO, is an ketoglutarate dependent nucleic acid demethylase protein. Its function is similar to the product of ABH2 and ABH3 gene in human genome. Under the condition of oxygen, Fe(II) and vitamin C induction, it could catalyze the demethylation of 3-methyl thymine in single stranded DNA and 3-methyl uracil in single-stranded RNA, and the demethylation of 3-methyl uracil is more apparent. FTO is the components of regulation of food intake and energy homeostasis. The imbalance of this approach will directly or indirectly lead to the accumulation of body fat and weight gain. FTO may play an important role in appetite control. However, the functions of FTO remain unclear. The study related to FTO protein has become a hot spot in the biomedical field.Spectroscopic method take more advantages, such as high sensitivity, good selectivity and simplicity, et al. It can provide related molecular structure and conformation information of the interaction between the protein and the drug. In this thesis,ultraviolet-visible absorption spectroscopy, fluorescence spectroscopy, synchronous fluorescence spectroscopy, three-dimensional spectroscopy and molecular modeling are employed to study the interactions between the fat mass and obesity associated protein(FTO) and small drug molecules or structural analogs under mimic physiological condition. The mechanism of the interaction between protein and drugs,it’s binding constant, combination distance, binding sites, binding force, protein conformation change and impact of environmental factors(such as buffer solution,p H value and ionic strength) on reaction are demonstrated. The research results will aid in understanding how the FTO gene mutation associated with obesity, and the new pathway related to obesity. The gene may be a useful target for new slimming products.The first chapter summarized the common research methods and its principle of the interaction between protein and drugs, the content and significance of theThe two chapter introducted the interaction between FTO and five pyrazole compounds under mimic physiological condition. The research indicate that the intrinsic fluorescence quenching of FTO caused by five pyrazole compounds is static quenching. Hydrophobic interaction forces might play the major role in the interactions of FTO with compound 1a~1d, but the acting forces are mainly vander Waals forces and hydrogen bonds in the interactions of FTO with 1e. Compared to other four pyrazoles analogs, compound 1e have a stronger quenching ability and affinity, and the absence of benzene ring might be responsible for the phenomenon.There is no apparent change in the polar of microenvironment surrounding where tyrosine and tryptophan residues.The three chapter study the interaction between FTO and three 1,3,4-oxadiazole(thiadiazole) analogs under mimic physiological condition. The 1,3,4-oxadiazole(thiadiazole) analogs quench the fluorescence of FTO through static quenching mechanism, and the stability of the complex would increases with increasing temperature. 2c is the strongest quencher, and the position of nitro group in compound may impact on binding. The polar of microenvironment surrounding where tyrosine and tryptophan residues, as well as the conformation of FTO changed after the combination of proteins. Hydrophobic interactions play a primary role in the binding process.The four chapter investigated the interaction between FTO and three nucleoside analogues. The three nucleoside analogues can quench the fluorescence of FTO, and the quenching mechanism is static quenching. Morever, the stability of the ground state complex would increases with the rising temperature. Results show that intermolecular forces are mainly hydrophobic interaction. The quenching ability and affinity of compound 3b was greater than other two nucleoside analogues. The category of groups attached to the nitrogen atom has important influence on the binding, resulting in existing difference of the relative interaetion strength between three nucleoside analogues and FTO. The polar of microenvironment surrounded tryptophan residues enhance.The five chapter investigated the interaction between FTO and three macrolidecompound. The quenching mechanism of macrolide compound with FTO is static quenching. The stability of 4b and 4c with FTO generating complex increases with increasing temperature, and hydrophobic forces play a significate role in the formation process. However, the stability of complex decreases with rising temperature, in addition to the hydrophobic interaction, hydrogen bonding and electrostatic interactions may be also involved. The quenching ability of 4a was greater than other two macrolide compound. The polar of microenvironment surrounding where tyrosine and tryptophan residues, as well as the conformation of FTO changed.The six chapter investigated the interaction between FTO with two kind of alkaloids(theophylline and caffeine). Research suggest that two kind of alkaloids quench the intrinsic fluorescence of FTO through the formating of complex. The polar of microenvironment surrounding where tyrosine and tryptophan residues, as well as the conformation of FTO changed. The stability of complex increases with increasing temperature, and the binding ablity of caffeine is much stronger. The methyl group attach to nitrogen atom in heterocyclic may reinforce the binding of caffeine with FTO.