荧光光谱研究吡虫啉与牛血清白蛋白的相互作用

Studies of Interaction Between Imidacloprid and Bovine Serum Albumin by Fluorescence Quenching Method

运用荧光光谱、紫外光谱法研究了农药吡虫啉与牛血清白蛋白(BSA)的相互作用。实验结果表明,农药分子与BSA形成基态复合物导致BSA内源荧光猝灭,猝灭机理主要为静态猝灭和非辐射能量转移。测定了不同温度下该反应的表观结合常数KA、结合位点数n及结合热力学参数,热力学参数的变化表明上述作用过程是自由能降低的自发分子间作用过程,农药分子与BSA之间以氢键和范德华作用力为主;根据F rster能量转移理论,测得供体与受体间结合距离r与能量转移效率E;并用同步荧光技术考察了农药分子对BSA构象的影响。

The interaction between imidacloprid and bovine serum albumin （BSA） was investigated using fluorescence and UV/Vis spectroscopy. The experimental results showed that the fluorescence quenching of BSA by imidacloprid was a result of the formation of imidacloprid-BSA complex and both static quenching and nonradiative energy transferring occurred in the fluorescence quenching. The binding site number n, apparent binding constant KA and corresponding thermodynamic parameters were measured at different temperatures. The process of binding imidacloprid molecule on BSA was a spontaneous molecular interaction procedure in which Gibbs free energy decreased. Hydrogen bonds and van der Waals force played a major role in stabilizing the complex. The binding distance r and energy-trausfer efficiency E between imidacloprid and BSA were obtained according to fluorescence resonance energy transfer. The effect of imidacloprid on the conformation of BSA was analyzed using synchronous fluorescence speetrocopy.