神经红蛋白突变体Tyr44Phe的制备、表征和稳定性研究  

Preparation,Characterization and Stability of Neuroglobin Mutant Tyr44Phe

作　　者：李海丽[1] 李连之[1,2] 郭玉静[1] 田素燕[1] 薛泽春[1] 姜玉岗[1] 

机构地区：[1]聊城大学化学化工学院,聊城252059 [2]南京大学配位化学国家重点实验室,南京210093

出　　处：《高等学校化学学报》2009年第5期928-933,共6页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:20471025)资助

摘　　要：构建了突变体蛋白Tyr44Phe的基因,进行了蛋白的表达、分离纯化、谱学表征和稳定性研究.由电喷雾质谱所得突变体蛋白的分子量与理论值一致;UV-Vis吸收光谱、荧光光谱和圆二色光谱表明,Tyr44Phe的点突变虽没有改变血红素的六配位结构,但对血红素的构象有所影响.突变体蛋白的热、酸稳定性研究表明,定点突变降低了血红素与蛋白肽链之间的结合力,导致血红素易从疏水腔中脱出,说明Tyr44对蛋白的结构稳定性起一定的作用.Neuroglobin（Ngb） is a recently discovered member of the hemoglobin superfamily in nervous system of vertebrates. Tyr44 nearing bis-histidyl ligand His64 contacts with one of the heme propionates by hydrogen bonds, which may involue in the stabilization for the hexacoordinate state of neuroglobin. In order to investigate the role of Tyr44 in structural stabilization of neuroglobin, the neuroglobin mutant Tyr44Phe gene was constructed by site-directed mutagenesis, and the mutant protein was expressed, purified and characterized speetroseopicaly, and its stability was also studied. The electrospray ionization mass spectroscopy result show that the molecular weight of the mutant Tyr44Phe corresponds with the theoretical value. The UV-Visible spectra, fluorescence spectra and circular diehroism （CD） spectra of mutant Tyr44Phe indicated that the mutagenesis doesn＇t change neuroglobin＇s bis-histidyl heine hexacoordination, but has an effect on heme configuration. Results of stability towards heat and acid show that the mutagenesis decreases the interaction of heme with peptide chain and the heme＇s hydrophobic cavity becomes flexible, which proves that Tyr44 plays an important role in neuroglobin structural stability.

关 键 词：神经红蛋白 突变体Tyr44Phe 稳定性 

分 类 号：O629.73[理学—有机化学] Q518.2[理学—化学]