The EPR spectrum for CuB in cytochrome c oxidase.
The EPR spectrum for CuB in cytochrome c oxidase.
复制标题
细胞色素 c 氧化酶中 CuB 的 EPR 谱图。
DOI：
10.1016/s0162-0134(00)00189-6
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发表时间：
2001
影响因子：
3.9
通讯作者：
Symons,MC
中科院分区：
文献类型：
--
作者：
Pezeshk,A;Torres,J;Wilson,MT;Symons,MC
将处于静息状态的细胞色素 c 氧化酶 (CcO) 在饱和硫酸铵中室温孵育过夜，产生单个 Cu(II) 中心特有的 EPR 信号。从g||和A||值可以得出结论，这是一个方形平面2型铜中心，超精细分裂表明平面内存在三个几乎相等的14N核。表明该中心也是通过在 10% 甲醇中孵育酶然后直接照射而形成的，一定是 CuB 中心。该 2 型铜 EPR 光谱与报道的从大肠杆菌中分离的细胞色素 bo3 复合物的 CuB 的 EPR 光谱相同；以及磺基甜菜碱 12 热处理细胞色素 c 氧化酶复合物的 EPR 谱图。有人认为，系统中的一个小扰动会导致血红素 a3-CuB 双核中心的磁耦合解耦和 2 型 EPR 信号的出现。
Incubation of cytochrome c oxidase (CcO) in its resting state in saturated ammonium sulfate, at room temperature overnight, gave EPR signals characteristic of a single Cu(II) center. From the g||and A||values it is concluded that this is a square-planar type 2 copper center, and superhyperfine splitting shows the presence of three nearly equivalent14N nuclei in the plane. It is suggested that this center, also formed by incubating the enzyme in 10% methanol followed by direct irradiation, must be the CuBcenter. This type 2 copper EPR spectrum is identical to the EPR spectrum of CuBreported for the isolated cytochrome bo3complex from Escherichia coli; and to the EPR spectrum reported for the sulfobetaine 12 heat-treated cytochrome c oxidase complex. It is argued that a small perturbation in the system causes decoupling of the magnetic coupling of the heme a3–CuBbinuclear center and the appearance of the type 2 EPR signal.