Spectroscopic Study on Interaction of Rodenticide Brodifacoum with Bovine Serum Albumin
Spectroscopic Study on Interaction of Rodenticide Brodifacoum with Bovine Serum Albumin
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DOI：
10.3964/j.issn.1000-0593(2009)11-2998-05
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发表时间：
2009-11-01
影响因子：
0.7
通讯作者：
Duan Zhi-qing
中科院分区：
文献类型：
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作者：
Duan Yun-qing;Lei Huan-gui;Duan Zhi-qing
在生理条件下，用紫外光谱、荧光光谱和同步荧光光谱研究了抗凝血灭鼠剂溴地库（3-[3-（4 '-溴苯基-4）1，2，3，4-四氢萘-10]-4-羟基香豆素）与牛血清白蛋白（BSA）的相互作用。结果表明，溴地库对牛血清白蛋白的内源荧光有猝灭作用。是溴鼠灵-BSA复合物形成的结果。这种猝灭主要是由于静态荧光猝灭。根据双倒数Lineweaver-Burk图和lg[（F-0 - F）IF] - lg[Q]图的猝灭函数计算了不同温度下的猝灭速率常数（K-SV）、结合位点数（n）和结合常数（K-A）。热力学参数表明，结合过程是一个自发的分子间相互作用，疏水力在稳定溴鼠灵BSA复合物中起主要作用。根据Forster非辐射能量转移理论，求得大隆与BSA在20 ℃和30 ℃时的结合距离r分别为2.84和2.87 nm。BSA和溴鼠灵-BSA的同步光谱表明，溴鼠灵的存在改变了BSA的构象。结合模式和作用机理为：溴鼠灵分子通过静电作用与BSA疏水空腔上带电荷的氨基酸残基紧密结合，并通过疏水作用力与BSA疏水空腔内的Trp 212残基结合，从而改变Trp残基周围的微环境。这种相互作用阻止了酪氨酸残基与色氨酸残基之间的能量转移，并导致酪氨酸残基与溴鼠灵之间的非辐射能量转移，最终导致BSA的内源荧光猝灭。
The mutual interaction of bovine serum albumin (BSA) with brodifacourn (3-[3-(4'-bromophenyl-4)1,2,3,4-tetralin-10]-4-hydroxyl-coumarin), an anticoagulant rodenticide, was investigated by ultra-violet spectroscopy, flurorescence spectroscopy and synchronous fluorescence spectroscopy under physiological conditions. It was proved that the intrinsic fluorescence quenching of BSA by brodifacourn. was the result of the formation of brodifacoum-BSA complex. And this quenching is mainly due to static fluorescence quenching. The quenching rate constant (K-SV), binding site number (n) and binding constant (K-A) at different temperatures were calculated from the double reciprocal Lineweaver-Burk plots and the quenching function of lg[(F-0 - F) IF] - lg[Q] plots. The thermodynamic parameters indicated that the process of binding was a spontaneous molecular interaction and the hydrophobic force played a major role in stabilizing the brodifacoum BSA complex. The binding distance r between brodifacoum and BSA was 2.84 and 2.87 nm at 20 and 30 degrees C, respectively, which was obtained based on Forster theory of non-radiation energy transfer. The synchronous spectroscopy of BSA and brodifacoum-BSA revealed that the BSA conformation had changed in the presence of brodifacoum. The binding mode and interaction mechanism were suggested as follows: brodifacoum molecules are closed with amino acid residues with electric charge on the hydrophobic cavities of BSA by electrostatic interaction, and binded to the Trp212 residues inside of BSA hydrophobic cavities by hydrophobic interaction force, thereby changed the microenvironment around the Trp residues. The interaction prevented the energy transfer between Tyr and Trp residues, moreover, caused to a non-radiation energy transfer from Trp residues in BSA to brodifacoum, and finally leaded of the quenching the intrinsic fluorescence of BSA.