荧光光谱法研究核黄素与核黄素结合蛋白的相互作用

摘要

运用荧光光谱研究了核黄素与核黄素结合蛋白的相互作用,并探讨了两者间的结合类型、结合常数、结合过程中热力学参数和能量转移.结果表明:核黄素结合蛋白内源荧光的猝灭是由于核黄素与蛋白质之间形成复合物,并符合静态猝灭机理.298,308,318 K下核黄素与核黄素结合蛋白的结合常数分别为:5.35×108,1.54×108,0.56×108 L· mol-1.热力学数据表明核黄素与核黄素结合蛋白之间主要作用力为氢键和范德华力.F(o)rster能量转移理论确定了核黄素与核黄素结合蛋白的作用距离与能量转移效率分别为0.70 nm与0.39.利用同步荧光光谱研究了核黄素结合蛋白与核黄素结合过程中构象的变化.%The interaction between riboflavin and egg white riboflavin binding protein (RBP) was investigated using fluorescence spectroscopy. The binding mode, binding constants, thermodynamic parameters between riboflavin and RBP and energy transfer were studied. The experimental results showed that riboflavin has the ability to quench the intrinsic fluorescence of RBP because of a complex formed, and the quenching mechanism is static quenching. The binding constants were 5. 35 × 108, 1. 54 × 108, 0. 56×108 L ? Mol-1 at 298, 308 and 318 K, respectively. The thermodynamic parameters were calculated, which suggested hydrogen bonds and Van der Waals played a major role in the interactioa The distance and efficiency of energy transfer between riboflavin and RBP were 0. 70 nm and 0. 39, respectively, based on the theory of Forster nonradiative energy transfer. Furthermore, the synchronous fluorescence spectroscopy was utilized to investigate the conformational transformatioa