Binding mechanism between bovine serum albumin and echinacoside / 中草药

ABSTRACT

Objective: To explore the binding mechanism between echinacoside (ECH) and serum albumin (SA). Methods: The binding parameters were detected by spectrum experiment under physiological conditions, and the molecular modeling techniques had been used to investigate the binding mechanism between ECH and bovine serum albumin (BSA). Results: Molecular docking revealed that ECH binded to BSA mainly by hydrogen bonds and van der Waals forces, and there was a hydrophobic interaction. The results from spectroscopy indicated that the drug could bind with BSA to form static complex with significantly strong bond. The value of binding distances (r) was low, which indicated the occurrence of energy transfer. ECH affected the conformation of micro-domain and changed the hydrophobicity of the binding domain. The fluorescence phase diagram revealed that the changes on the conformational pattern of proteins had been affected by drug conformed to the "all-or-none" pattern. According to the obtained thermodynamic parameters, it also showed that the main interactional force of ECH binding with BSA was hydrogen bonds and van der Waals forces. The fluorescence polarization proved quantitatively that ECH-BSA generated a non-covalent complex. Conclusion: The experimental results agree with computer molecular modeling, which provides helpful reference for the interaction mechanism of ECH binding with BSA.