Spectrometric And Atomic Force Microscopy Study Of The Interaction Between Small Molecule Drug And Human Serum Albumin

Protein is functional and biological macromolecules within cells. It has a carrying and storage capabilities, and its biological function is closely related to its particular structure. Serum albumin is the most important and abundant transporter in the blood plasma. Generally speaking, drug will bind with the serum albumin when it gets to the plasma and then transport to various parts of the body to play a pharmacodynamics. Therefore, by means of the investigatment on the binding mechanism of drug with serum albumin at the molecular level, we would not only able to understand drug transport and metabolism and guide clinical rational use of medicines, but also can suggest new approaches to drug therapy and design. This thesis used different optical techniques, atomic force microscope (AFM) and molecule modeling methods to investigate the interactions of syringin, costunolide, dehydrocostuslactone and 2-Mercaptobenzimidazole with human serum albumin (HSA). The thesis is mainly consists of the following four chapters:In Chapter 1, a brief introduction was given to the development of small molecules and protein interaction. The methods for the study of the interaction between small molecules and proteins were reviewed. Finally, the structure and function of HSA and many small molecules which can interact with protein were summarized briefly.In Chapter 2, the interaction of a kind of Chinese herbal active component syringin and HSA has been investigated by fluorescence, UV, CD, FTIR spectroscopic, AFM and molecular modeling methods. The structural characteristics of HSA and syringin were studied by CD and FTIR spectroscopic. Binding constant and binding sites number were determined by Bhattacharya equation. The enthalpy changes and the entropy changes were calculated according to the Van't Hoff equation. These results indicated that syringin binds to HSA mainly driven by hydrophobic force interaction while electrostatic force interaction can also not be excluded.In Chapter 3, the interaction of costunolide/dehydrocostuslactone with HSA was investigated by molecule modeling, AFM and different optical techniques. The quenching constants of costunolide/dehydrocostuslactone with HSA were measured at different temperature, and quenching mechanism was suggested as static quenching for costunolide/dehydrocostuslactone- HSA system. Moreover, this study has found that the binding constant of HSA with costunolide is stronger than that of HSA with dehydrocostuslactone. In Chapter 4, the interaction between 2-Mercaptobenzimidazole and HSA was studied by steady state and time resolved fluorescence, FTIR, Raman spectroscopic, AFM and molecular modeling methods in physiological buffer solution. Steady state and time resolved fluorescence spectroscopy suggested that the quenching mechanism of 2-Mercaptobenzimidazole–HSA interaction was a dynamic quenching procedure. The quenching constants of the interaction between 2-Mercaptobenzimidazole and HSA were measured by Stern-Volmer equation at different temperature. Furthermore, AFM results showed that the dimension of HSA molecules became more swollen after binding with 2-Mercaptobenzimidazole.