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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Cu~(2+)离子与Cygb的相互作用。结果表明,当Cu~(2+)离子加入到Cygb溶液中后,Cygb在280nm处的紫外吸收强度增大,说明Cu~(2+)与Cygb发生了相互作用;Cu~(2+)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,Cu~(2+)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Cu~(2+)对Cygb的键合部位更接近于色氨酸。圆二色光谱研究表明,Cu~(2+)对Cygb的二级结构未引起明显变化。
Cycloglobulin (Cygb) is a member of the globulin family recently found in vertebrates that has the “3 + 3” -type a-helical sandwich fold structure of a typical globin. The interaction between Cu 2+ ions and Cygb was studied by UV-visible absorption spectroscopy, fluorescence spectroscopy, synchronous fluorescence spectroscopy and circular dichroism (CD) spectroscopy. The results showed that the UV absorption intensity of Cygb at 280 nm increased when Cu 2+ ions were added to Cygb solution, indicating that Cu 2+ interacted with Cygb. Endogenous fluorescence of Cygb quenches, quenching its static quenching. Simultaneous fluorescence spectroscopy showed that Cu 2+ could slightly change the microenvironment of tryptophan and tyrosine, which was closer to that of Cygb than that of tyrosine For tryptophan. Circular dichroism spectroscopy showed that the secondary structure of Cygb did not change obviously due to Cu 2+.