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作 者:颜承农[1] 张华新[1] 刘义[2] 梅平[1] 李克华[1] 童金强[1]
机构地区:[1]长江大学化学与环境工程学院,荆州434020 [2]武汉大学化学与分子科学学院,武汉430072
出 处:《化学学报》2005年第18期1727-1732,共6页Acta Chimica Sinica
基 金:国家自然科学基金(No.30170010);湖北省教育厅重点(No.2003A003);湖北省自然科学基金(No.2005ABA067)资助项目.
摘 要:在模拟动物体生理条件下,用荧光光谱和紫外-可见吸收光谱法研究了在不同温度下,百草枯(PQ)与牛血清白蛋白(BSA)结合反应的光谱行为.试验发现,PQ对BSA有较强的荧光猝灭作用.用Stern-Volmer和Lineweaver-Burk方程分别处理试验数据,发现BSA与PQ发生反应生成了新的复合物,属于静态荧光猝灭,发生分子内的非辐射能量转移.根据F?rster的偶极-偶极非辐射能量转移理论计算出结合位置距离212位色氨酸残基2.07nm.由Lineweaver-Burk方程求出了不同温度下反应时复合物的形成常数KLB(297K:2.035×104L?mol-1;304K:3.256×104L?mo-1;311K:2.889×104L?mol-1)及对应温度下结合反应的热力学参数(?H=18.50kJ?mol-1;?S=144.7J?K-1/145.2J?K-1/141.0J?K-1;?G=-24.50kJ?mol-1/-25.66kJ?mol-1/-25.36kJ?mol-1),证明二者主要靠疏水作用力结合.同时用三维荧光光谱及同步荧光光谱法探讨了PQ对BSA构象的影响,为预防和医治PQ中毒提供了重要依据.Under the imitated physiological condition of animal body, the binding of paraquat to bovine serum albumin (BSA) was studied by fluorescence spectrum and ultra-violet spectrum. It was shown that this compound has a quite strong ability to quench the fluorescence launching from BSA. After analyzing the fluorescence quenching data according to Stern-Volmer equation and Lineweaver-Burk double-reciprocal equation, we found that BSA had reacted with paraquat and formed a certain new compound. The quenching belonged to static fluorescence quenching, with non-radiation energy transfer happening within single molecule. The binding locality was an area 2.07 nm away from tryptophan residue-212 in BSA based on F(oe)rster's non-radiation energy transfer mechanism. According to Lineweaver-Burk equation, KLB (297 K: 2.035×10^4 L·mol^-1; 304 K: 3.256×10^4 L·mo^-1; 311 K: 2.889×10^4 L·mol^-1), the forming constants of the compound at different temperatures and the thermodynamic parameters (△H^⊙ = 18.50 kJ·mol^-l; △S^⊙ = 144.7 J·K^-1/145.2 J·K^-1/141.0 J·K^-1; △G^⊙ =-24.50 kJ·mol^-l/-25.66 kJ·mol^-l/-25.36 kJ·mol^-1) at correspondence temperatures were obtained. The latter shows that binding power between them is mainly the hydrophobic interaction. The effect of paraquat on the conformation of BSA was analyzed by three-dimensional fluorescence spectra, contour spectra and synchronous spectra, and some useful information was offered for preventing animals from infecting paraquat and curing those who had caught it.
关 键 词:百草枯 牛血清白蛋白 结合反应 热力学参数 吸收光谱 三维荧光光谱 同步荧光光谱法 结合作用 非辐射能量转移 荧光猝灭作用
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