铽(Ⅲ)与PvdA作用的光谱研究  

Spectroscopic Studies on the Binding of Terbium to PvdA

作　　者：张文龙[1] 许彩虹[1] 杨斌盛[1] 

机构地区：[1]山西大学分子科学研究所,化学生物学与分子工程教育部重点实验室,太原030006

出　　处：《无机化学学报》2014年第1期106-112,共7页Chinese Journal of Inorganic Chemistry

基　　金：山西省留学归国基金(No.201013)资助项目

摘　　要：Pyoverdine A(PvdA)是荧光假单胞菌分泌的一种水溶性较高的黄绿色荧光铁载体。在50 mmol·L-1Tris-HCl,pH 8.0条件下,使用紫外-可见吸收差光谱、荧光光谱研究了铽(Ⅲ)与荧光铁载体PvdA的结合。结果表明铽(Ⅲ)可与PvdA结合形成1:1的配合物,条件结合常数为(4.44±0.82)×1014mol-1·L。在生理条件下,PvdA可竞争伴清蛋白N-,C-端结合的铽(Ⅲ)形成Tb-PvdA配合物;Tb-PvdA与荧光假单胞菌细胞表面受体FpvA结合形成Tb-PvdA-FpvA复合物。PvdA is a siderophore, secreted by Pseudomonas aeruginosa in order to get access to iron. PvdA in 50 mmol. L-1Tris-HCl, pH 8.0 was titrated with acidic solutions of Tb3＋ and the binding of Tb3＋ to PvdA was followed from changes both in the difference UV-Vis spectra at 380 nm and in fluorescence at 457 nm. The 1：1 stable complex of Tb-PvdA can be confirmed from spectral titration curves. Using EDTA as a competitor the conditional binding constant of the complex was measured to be （4.44±0.82）×10^14 mol-1.L. The formed Tb-PvdA from the reaction between PvdA and Tb3＋ saturated ovotansferrin can be followed by measuring the fluorescence emission of Tb3＋ at 548 nm, demonstrating that the binding of PvdA for Tb3＋ is stronger than that of apoovotransferrin. Furthermore, Tb-PvdA interaction with the PvdA-Fe outer membrane transporter, FpvA, of Pseudomonas aeruginosa could be followed by fluorescence resonance energy transfer between the tryptophans of FpvA （donor） and PvdA （acceptor）.

关 键 词：TB3+ PvdA 光谱 蛋白质 

分 类 号：O614.341[理学—无机化学]