大黄酸锌配合物与牛血清白蛋白相互作用的研究

Interaction of ZnⅡ Complex of Rhein with Bovine Serum Albumin

采用荧光猝灭光谱、同步荧光光谱、紫外光谱和圆二色光谱,研究了大黄酸锌配合物(Rhein-Zn)与牛血清白蛋白(BSA)之间的相互作用。结果表明,Rhein-Zn能显著猝灭BSA的内源荧光并以静态猝灭为主;Rhein-Zn与BSA结合常数分别为1.3×107(22℃)、1.6×106(27℃)和1.0×105L/mol(36℃),根据热力学参数判断Rhein-Zn与BSA之间的作用力主要为范德华力和氢键;依据F rster的偶极-偶极非辐射能量转移理论,计算出Rhein-Zn与BSA之间的结合距离为3.20 nm;同步荧光光谱和圆二色光谱研究表明Rhein-Zn能够使BSA构象发生变化。

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.