吴茱萸碱与人血清白蛋白相互作用的荧光光谱研究

Study of intermolecular interaction between evodiamine and human serum albumin by using fluorescence spectroscopy

采用荧光光谱法,研究了在不同温度与生理pH条件下吴茱萸碱同人血清白蛋白的相互作用。研究结果表明,吴茱萸碱可有效地猝灭人血清白蛋白的荧光发射,并且其猝灭常数与溶液温度成反比,其猝灭机制为吴茱萸碱同人血清白蛋白形成了稳定的非共价复合物而引起的静态猝灭。复合物稳定常数大于10 4 L/mol,复合物中主客体之比为1∶1。依照Van t Hoff方程获对荧光光谱结果进行计算得了不同温度下吴茱萸碱与人血清白蛋白相互作用的热力学参数,其中ΔG、ΔH和ΔS均小于0,由此可见推动此复合物形成的主要作用力是氢键和范德华力。进一步采用了同步荧光光谱法研究了吴茱萸碱与人血清白蛋白可能的结合位点,并且通过分子对接模拟推测了复合物的结构,结果表明吴茱萸碱最可能结合在人血清白蛋白的Trp214残基附近。

The interaction between evodiamine and human serum albumin at different temperature and physiological pH was studied by fluorescence spectroscopy.The results show that evodiamine can effectively quench the fluorescence emission of human serum albumin,and its quenching constant is inversely proportional to the solution temperature.The quenching mechanism is the static quenching caused by the formation of a stable non-covalent complex between evodiamine and human serum albumin.The stability constant of the complex is greater than 10 4 L/mol and the ratio of the host to the guest in the complex is 1∶1.According to Van t Hoff s equation,fluorescence spectral results at different temperatures are calculated.The thermodynamic parameters includingΔG,ΔH andΔS,which are all less than zero,are calculated for the interaction between evodiamine and human serum albumin.It is believed that the driving forces for promoting the complex formation are hydrogen bonding and Van der Waals force.In this work,the potential binding sites of evodiamine and human serum albumin are further studied by synchronous fluorescence spectrometry and the structure of the complex is speculated by molecular docking simulation either.The results showed that evodiamine is most likely to bind near Trp214 residue of human serum albumin.