OBJECTIVETo study the molecular action mechanism of active constituents desoxyrhaponticin (DES) and human serum albumin (HSA).

METHODUnder the simulated physiological condition, computer analog technology, fluorescent spectrometry and ultraviolet spectrum were combined to study the binding mechanism between drug and protein.

RESULTMolecular modeling was adopted to establish the binding model between DES and HSA, suggesting that the interaction force maintaining drug and protein is mainly the hydrophobic interaction with a hydrogen-bond interaction. The results from spectroscopy indicated that the interaction between DES and HSA is a dynamic binding process with a high intensity. The value of the binding distance (r) between DES and HSA was low, which demonstrate the occurrence of energy transfer. DES made an impact on HSA' structural domain microcell conformation, which resulted in hydrophobic changes in binding areas. According to the fluorescent phase diagram technical analysis, the changes in the DES-HSA reaction conformational pattern showed a "two-state" model. According to the obtained thermodynamic parameters for the DES-HSA interaction, the interactional force between DES and HSA was mainly a hydrophobic interaction. The fluorescence polarization proved that a non-covalent compound was generated during the interaction between DES and HSA.

CONCLUSIONThe spectrum experiment showed consistent results with the computer analog technology, which could provided certain reference for studies on the interaction between DES and HSA.