论文部分内容阅读
应用荧光光谱法结合紫外-可见分光光度法研究了土大黄苷(rhaponticin,RT)与人血清白蛋白(human serum albumin,HSA)的结合反应机制,并考察了金属离子的介导作用。依据不同理论模型测定了反应体系的结合常数K、结合位点数n并进行了分析比较,探讨了荧光猝灭机制。根据Frster非辐射能量转移机制确定了授体-受体间结合距离和能量转移效率。采用同步荧光技术考察了RT对HSA分子构象的影响。结果表明,不同理论模型计算出的结合参数基本相符并显示出RT与HSA的结合反应为形成静态复合物,说明RT在生理条件下能被HSA载运至靶位发挥药效。RT对HSA分子结构域微区构象产生影响,造成亚结构域IIA、IIB的疏水性改变。Co(Ⅱ)、Ni(Ⅱ)的介导作用在RT-HSA反应中起桥联作用并增强RT-HSA的相互作用,即在生理条件下,Co(Ⅱ)、Ni(Ⅱ)对RT药效的发挥起促进作用。
The binding mechanism of rhaponticin (RT) to human serum albumin (HSA) was studied by fluorescence spectroscopy combined with ultraviolet-visible spectrophotometry. The mediation of metal ions was also investigated. According to different theoretical models, the binding constant K and the number of binding sites n of the reaction system were measured and compared, and the fluorescence quenching mechanism was discussed. The donor-acceptor binding distance and energy transfer efficiency were determined according to the Frster non-radiative energy transfer mechanism. Simultaneous fluorescence was used to investigate the effect of RT on the conformation of HSA. The results show that the binding parameters calculated by different theoretical models are basically consistent and show that the binding reaction between RT and HSA forms a static complex, indicating that RT can be transported to the target site by HSA under physiological conditions. RT affects the micro-domain conformation of the HSA molecular domain, resulting in a change in the hydrophobicity of the subdomains IIA, IIB. The mediation of Co (Ⅱ) and Ni (Ⅱ) plays a role of bridging and enhancing the interaction of RT-HSA in RT-HSA reaction. Under the physiological conditions, Effective play a catalytic role.