琥珀酸脱氢酶的x光光谱研究

使用同步辐射光源,以荧光模式研究了琥珀脱氢酶的X光吸收光谱,表明所含的铁硫蛋白中,铁处于硫的四面体配位中;由氧化态及还原态的铁K边化学位移大小可知每个铁原子得失电子个数,SDHu(A)为0.39,,SDH(I)为0.30,,都比1小得多;表明有配位体容纳电子的作用,也表明有重组活性的SDH(A),具有较强的接受电子能力.文中引用量子化学计算结果对光谱现象予以合理的解释.

X-RAY SPECTROSCOPY STUDIES OF SUCCINATE DEHYDROGENASE

X-ray absorption spectra of SDH have been studied in the fluoresence mode with synchrotron radiation lignt source.The results show that Fe in these iron-sulfur proteins is located in the center of tetrahydral sulfur atoms; the numbers of electrons gained in the reduction,calculated from the chemical shifts of Fe K edge in oxidized reduced and states of SDH,are 0.39 for SDH(A) and 0.30 for SDH (I) ,much less than 1.This means that the electronic charge could be spread into the coordinators and the reconstitutive SDH has higher ability of accepting electrons. The spectra results can be explained very well with the quantum chemistry calculation cited here.