Interaction of ZnII Complex of Rhein with Bovine Serum Albumin
The interaction between Rhein-Zn and bovine serum albumin(BSA) was investigated by fluorescence quenching spectra,synchronous fluorescence spectra,ultraviolet spectra and circular dichroism spectra.The results indicated that Rhein-Zn led to the intrinsic fluorescence quenching of BSA through a static quenching process.The binding constants(K) between Rhein-Zn and BSA were 1.3×107(22 ℃),1.6×106(27 ℃) and 1.0×105 L/mol(36 ℃),respectively.The binding power between Rhein-Zn and BSA is mainly H-bond and van der Waals force according to the thermodynamic parameters.The binding locality was found to be in a distance of 3.20 nm away from tryptophan residue in BSA based on Frster non-radiation energy transfer mechanism.The results of circular dichroism(CD) and synchronous fluorescence spectra showed that the binding of Rhein-Zn to BSA induced conformational changes in BSA.