异嗪皮啶与人γ球蛋白相互作用研究(英文)  

Interaction of isofraxidin with human gamma globulin

作　　者：雷瑞霞[1,2] 刘永春[2] 杜娟[1] 杨正银[1] 姚小军[1] 胡之德[1] 

机构地区：[1]兰州大学化学化工学院,兰州730000 [2]陇东学院化学化工学院,甘肃庆阳745000

出　　处：《兰州大学学报（自然科学版）》2009年第3期92-100,共9页Journal of Lanzhou University(Natural Sciences)

基　　金：The National Natural Science Foundation of China(20475023);Natural Science Foundation of GansuProvince(0710RJZA012);Gansu College and University Science and Research Project for Supervisor ofGraduate Students(0510-06)

摘　　要：利用荧光光谱和FT-IR方法在体外研究了异嗪皮啶与人γ球蛋白(HGG)的相互作用,利用Sips和Gibbs-Helmholtz方程计算了不同温度下结合反应的亲和力常数和热动学参数,利用Docking方法研究了其相互作用模式。Sips图谱结果表明,异嗪皮啶与HGG之间主要存在两类结合位点,以及基于范德华力和氢键的非特异性的相互作用,而且结合反应是熵驱动的自发的放热结合过程。在297, 303,310,317 K下的亲和力常数分别为10.708,9.152,7.084,5.386 L/mol。利用FT-IR光谱方法计算了在异嗪皮啶加入前后HGG二级结构的含量变化,结果表明加入异嗪皮啶后,蛋白质β结构含量降低,但是蛋白质典型的β-构型仍然保持。根据Frster能量转移理论,计算得到蛋白质色氨酸残基与异嗪皮啶的平均结合距离为3.57 nm。HGG可作为异嗪皮啶的体内转运蛋白。The interaction of isofraxidin with human immune gamma globulin （HGG） was studied in vitro by fluorescence spectra and FT-IR. The binding and thermodynamic parameters for the reaction were calculated according to Sips procedure and Gibbs-Helmholtz equation respectively at different temperatures. Molecular docking was used to calculate the interaction modes between isofraxidin and HGG. The Sips plots suggested that the binding of HGG to isofraxidin at 297, 303, 310 and 317 K was characterized by two binding sites with the average affinity constants k0 at 10.708, 9.152, 7.084, 5.386 L/mol, respectively. The binding process was exothermic, spontaneous and enthalpy driven. The binding was a non-specific interaction, mainly based on the interactions of Van der Waals forces and hydrogen bonds. The secondary structure compositions of free HGG and its isofraxidin complexes calculated quantitatively by the FT-IR spectrum results indicated that the β-structure compositions of HGG decreased in the presence of isofraxidin, but the typical β structural conformation of HGG was still retentive. The average binding distance between isofraxidin and the tryptophan residues in HGG （3.57 nm） was obtained on the basis of the theory of Forster energy transfer. The experimental results indicat that HGG could be used as a transfer for isofraxidin in vivo.

关 键 词：人γ球蛋白 异嗪皮啶 荧光淬灭 傅里叶变换红外光谱 

分 类 号：O621.25[理学—有机化学]