胞红蛋白(Cygb)是近期在脊椎动物中发现的一种球蛋白家族成员, 具有典型珠蛋白的“3+3”式的α-螺旋三明治折叠结构。 利用紫外可见吸收光谱、 荧光光谱、 同步荧光光谱及圆二色(CD)光谱法研究了Cu2+离子与Cygb的相互作用。 结果表明, 当Cu2+离子加入到Cygb溶液中后, Cygb在280 nm处的紫外吸收强度增大, 说明Cu2+与Cygb发生了相互作用; Cu2+使Cygb的内源性荧光发生猝灭, 其猝灭方式为静态猝灭。 同步荧光光谱研究表明, Cu2+可使色氨酸和酪氨酸的微环境发生较小的改变, 与酪氨酸相比Cu2+对Cygb的键合部位更接近于色氨酸。 圆二色光谱研究表明, Cu2+对Cygb的二级结构未引起明显变化。

Cytoglobin (Cygb), a recently discovered member of the vertebrate globin family, exhibits a traditional globin fold with a three-over-three α-helical sandwich. The interaction between copper(Ⅱ) ion (Cu2+) and Cygb has been investigated by UV-Vis, fluorescence, synchronous fluorescence and circular dichroism (CD) spectra. Results showed that the absorption intensity of Cygb at 280 nm increased and the intrinsic fluorescence of Cygb was quenched when Cu2+ was added. This fluorescence quenching of Cygb has been proven that it belongs to static quenching. The synchronous fluorescence spectra indicated that there were small changes about the microenvironment of tryptophan residues and tyrosine residues; furthermore, the binding site of Cu2+ is closer to tryptophan residues than tyrosine residues. No obvious change was observed about the secondary structure of Cygb with the addition of Cu2+ from the CD spectra.