Definition of the catalytic site of cytochrome c oxidase: specific ligands of heme a and the heme a3-CuB center.
Definition of the catalytic site of cytochrome c oxidase: specific ligands of heme a and the heme a3-CuB center.
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细胞色素c氧化酶催化位点的定义：血红素a和血红素a3-CuB中心的特异性配体。
DOI：
10.1073/pnas.89.11.4786
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发表时间：
1992
影响因子：
11.1
通讯作者：
Ferguson-Miller,S
中科院分区：
文献类型：
--
作者：
Shapleigh,JP;Hosler,JP;Tecklenburg,MM;Kim,Y;Babcock,GT;Gennis,RB;Ferguson-Miller,S
球形红细菌的三亚基aa 3型细胞色素c氧化酶（EC 1.9.3.1）在结构和功能上与更复杂的线粒体氧化酶同源。最大的亚基，亚基I，是高度保守的，并预测含有12个跨膜段，提供所有的配体的四个金属中心：血红素a，血红素a3，和CuB。多种光谱技术鉴定这些配体为组氨酸。我们已经使用定点突变改变所有保守的组氨酸从Rb的细胞色素c氧化酶亚基I内。sphaeroides通过光学吸收和共振拉曼光谱分析膜结合和纯化的突变蛋白表明His-102和His-421是血红素a的配体，而His-284、His-333、His-334和His-419连接血红素a 3-CuB中心。为了满足这种连接分配，含有这些组氨酸残基的螺旋II、VI、VII和X必须非常接近。这些数据提供了关于细胞色素c氧化酶催化核心的三维蛋白质结构的经验证据。
The three-subunit aa3-type cytochrome c oxidase (EC 1.9.3.1) of Rhodobacter sphaeroides is structurally and functionally homologous to the more complex mitochondrial oxidase. The largest subunit, subunit I, is highly conserved and predicted to contain 12 transmembrane segments that provide all the ligands for three of the four metal centers: heme a, heme a3, and CuB. A variety of spectroscopic techniques identify these ligands as histidines. We have used site-directed mutagenesis to change all the conserved histidines within subunit I of cytochrome c oxidase from Rb. sphaeroides. Analysis of the membrane-bound and purified mutant proteins by optical absorption and resonance Raman spectroscopy indicates that His-102 and His-421 are the ligands of heme a, while His-284, His-333, His-334, and His-419 ligate the heme a3-CuB center. To satisfy this ligation assignment, helices II, VI, VII, and X, which contain these histidine residues, must be in close proximity. These data provide empirical evidence regarding the three-dimensional protein structure at the catalytic core of cytochrome c oxidase.