Study On Binding Characteristic Of Flavonoids With BSA By Spectroscopic And Molecular Docking Methods

In vivo of natural organisms,the bioactive and pharmacologically active substances of all kinds of micromolecules must be revealed through the interaction with biological macromolecules. To study the interactions between biological macromolecules and micromolecules is the basic way to understand the biological effects and functions in various types of micromolecules, which is very important for better understanding pharmacodynamics, pharmacokinetics, pharmacology and toxicology of drugs as well.This paper studied the binding characteristics of quercetin and quercetin-3-O-?-D-glucose-7-O-?-D-gentiobiosiden with BSA (Bovine Serum Albumin) by using spectroscopic and molecular docking. Three molecular docking methods were used to dock 18 kinds of flavonoids and BSA study its binding properties. This rescrch provide reference information for the study of the mechanism of their interaction with the BSA and their drugs modified and functional health food research or applications.The binding characteristics of quercetin and BSA were studied by using spectroscopic combined with molecular docking. Results showed that quercetin could quench BSA intrinsic fluorescence regularly,quenching mechanism was static quenching; Quercetin with BSA's binding constants,binding sites,thermodynamic parameters were calculated to confirm the force between them is mainly hydrophobic force;binding constant K was 6.93 X 105 L/mol under 22?,binding sites n was 1.1467; Synchronization fluorescence spectroscopy studies have shown that the interaction between quercetin and BSA caused the conformational change in BSA. Molecular docking results indicated that the binding of quercetin within the hydrophobic cavity in subdomain ?A (site ?) of BSA,hydrophobic interactions play a main role there also exist hydrogen bonds and electrostatic force. Molecular docking results consist with the corresponding spectral results.The binding characteristics of quercetin-3-O-P-D-glucose-7-O-3-D-gentiobiosiden and BSA were studied systematically by using fluorescence spectroscopy,UV-vis absorption spectrum and molecular docking under physiological conditions in vitro. Binding constants, binding sites,thermodynamic parameters were calculated to confirm the force between quercetin-3-O-?-D-glucose-7-O-?-D-gentiobiosiden and BSA was mainly electrostatic interactions; Binding constant K was 4.37×105 L/mol under 22?,binding sites n was 1.1793; Synchronization fluorescence spectroscopy studies have shown that the interaction between quercetin-3-O-?-D-glucose-7-O-?-D-gentiobiosiden and BSA caused the conformational change in BSA. Molecular docking results indicated that the binding of quercetin-3-O-?-D-glucose-7--?-D-gentiobiosiden within the hydrophobic cavity in subdomain IIA (site I) of BSA,electrostatic force play a main role there also exist hydrogen bonds and hydrophobic interactions. Molecular docking results consist with the corresponding spectral results.Three molecular docking methods were used to dock the 18 kinds of quercetins and BSA and obtained binding site,binding force,hydrogen bonds distance,the number of hydrogen bonds, fluorescent amino acids distance and scoring information of 18 kinds of flavonoids and BSA binding in three molecular docking way. The docking method one whose score greater than 4 indicate the binding mode of this way best meets 18 kinds of flavonoids and BSA. The docking method one's results showed that 18 kinds of flavonoids were combined in the BSA subdomain IIA,the combination of 18 kinds of flavonoids and BSA caused by several forces (hydrophobic interaction,hydrogen bonding,van der Waals and electrostatic force) combined effect. The main force,the number of hydrogen bonds,hydrogen bonds distance,fluorescent amino acids distance and the number of fluorescent amino acids of different compounds are different too. The docking results of quercetin and quercetin-3-O-?-D-glucose-7-O-?-D-glucoside in BSA consist with the previous fluorescence results at molecular docking mode one.