Degli Esposti M, Ballester F, Solaini G, Lenaz G
Biochem J. 1987 Jan 1;241(1):285-90. doi: 10.1042/bj2410285.
We have studied the c.d. spectra of the 'Rieske' iron-sulphur protein isolated from the ubiquinol: cytochrome c reductase (bc1 complex) of bovine heart mitochondria. Both the oxidized and the reduced form of the 'Rieske' protein display a series of well-resolved c.d. features resembling those reported for the 'Rieske'-type iron-sulphur protein purified from the bacterium Thermus thermophilus [Fee, Findling, Yoshida, Hille, Tarr, Hearshen, Dunham, Day, Kent & Münck (1984) J. Biol, Chem. 259, 124-133]. In particular, the difference spectra, reduced minus oxidized, of both proteins have a distinctive negative band at 497 nm. The c.d. features characteristic of the isolated 'Rieske' protein were found in the dichroic spectra of the whole bc1 complex in the region between 450 and 520 nm. The reduction of the enzyme by ascorbate or ubiquinol is accompanied by the formation of a negative band at about 500 nm that corresponds, in all its c.d. properties, to the specific dichroic absorption of the reduced 'Rieske' iron-sulphur protein.
细胞色素c还原酶（bc1复合物）中分离出的“里斯克”铁硫蛋白的圆二色光谱。“里斯克”蛋白的氧化态和还原态均显示出一系列分辨率良好的圆二色特征，类似于从嗜热栖热菌中纯化出的“里斯克”型铁硫蛋白所报道的特征[费伊、芬德林、吉田、希尔、塔尔、赫申、邓纳姆、戴、肯特和明克（1984年）《生物化学杂志》259卷，124 - 133页]。特别是，两种蛋白的差光谱（还原态减去氧化态）在497 nm处都有一个独特的负峰。在450至520 nm区域的整个bc1复合物的二色光谱中发现了分离出的“里斯克”蛋白的特征性圆二色特征。用抗坏血酸或泛醇还原该酶时，会伴随着在约500 nm处形成一个负峰，该负峰在所有圆二色特性上都与还原态“里斯克”铁硫蛋白的特定二色吸收相对应。
