氧化态和还原态细胞色素c氧化酶的X射线吸收边研究
X-ray absorption edge studies on oxidized and reduced cytochrome c oxidase.
作者信息
Hu V W, Chan S I, Brown G S
出版信息
Proc Natl Acad Sci U S A. 1977 Sep;74(9):3821-5. doi: 10.1073/pnas.74.9.3821.
The x-ray absorption edge spectra of the Cu and Fe-centers in oxidized and reduced cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase: EC 1.9.3.1) have been obtained using synchrotron radiation from the SPEAR storage ring at the Stanford Linear Accelerator Center. In addition, oxidized and reduced plastocyanin as well as a number of model copper compounds in various oxidation states were also examined. A comparison of the absorption edge fine structure of cytochrome oxidase with those of the models indicates that one of the two coopers in the oxidized protein is in the +1 oxidation state. Upon reduction of the protein with dithionite, the second copper becomes Cu(I). The shift in the Fe K-edge of cytochrome oxidase upon reduction is small (about 2 e V or 3 times 10(-19 J) and is comparable to that previously observed for the reduction of the heme iron of cytochrome c.
利用斯坦福直线加速器中心的SPEAR储存环产生的同步辐射，获得了氧化态和还原态细胞色素c氧化酶（亚铁细胞色素c：氧氧化还原酶：EC 1.9.3.1）中铜和铁中心的X射线吸收边谱。此外，还研究了氧化态和还原态质体蓝素以及多种处于不同氧化态的铜模型化合物。细胞色素氧化酶的吸收边精细结构与模型化合物的吸收边精细结构的比较表明，氧化态蛋白质中的两个铜原子之一处于+1氧化态。用连二亚硫酸盐还原蛋白质后，第二个铜原子变成Cu(I)。细胞色素氧化酶还原时Fe K边的位移很小（约2电子伏特或3×10⁻¹⁹焦耳），与先前观察到的细胞色素c血红素铁还原时的位移相当。
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