【摘要】 人类神经生长抑制因子(GIF)又称MT3,其α 结构域存在一个特殊的插入六肽,其中含有多个谷氨酸残基,这些谷氨酸残基被认为与GIF具有保护神经元活性有关.为更好地研究这些Glu的作用,分别制备了E55/58/60Q和E58K2个突变体蛋白并对其稳定性进行了初步研究.结果显示,突变体蛋白的一系列光谱性质同野生型MT3非常一致,对酸的稳定性和对EDTA及DTNB的反应性上,也都表现出同野生型蛋白相似的性质.实验表明MT3α 结构域插入段中的Glu残基对蛋白的金属 硫簇结构及其稳定性没有显著的贡献.更多还原

【Abstract】 Human growth inhibitory factor is a brain-specific metallothionein (MT3) and a hexapeptide insertion is present in its C-terminal of α-domain. This insertion comprises several glutamate residues, which are reported to be necessary for protection against the cytotoxicity. In order to clarify the role of these glutamate residues, two mutants of MT3, E58K and E55/58/60Q have been prepared, in which one or several glutamate residues are replaced by lysine or glutamine. After characterized by UV-Vis spectra and Raman spectra, a pH titration of mutants it’s the reaction with EDTA and DTNB were investigated. The results show that both the spectra and the reactions of mutants are similar to that of the wild type MT3. It seems that the glutamate residues in the hexapeptide insertion are not responsible for the structure and stability of metal-thiolate clusters of human MT3.更多还原