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.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
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.
