Properties of a copper-containing cytochrome ba3: a second terminal oxidase from the extreme thermophile Thermus thermophilus.
Properties of a copper-containing cytochrome ba3: a second terminal oxidase from the extreme thermophile Thermus thermophilus.
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DOI：
10.1073/pnas.85.16.5779
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发表时间：
1988-08
影响因子：
11.1
通讯作者：
B. Zimmermann;C. Nitsche;J. Fee;F. Rusnak;E. Münck
中科院分区：
文献类型：
--
作者：
B. Zimmermann;C. Nitsche;J. Fee;F. Rusnak;E. Münck
我们描述了一个交替的终端氧化酶中发现的嗜热栖热菌质膜，并指定它的细胞色素ba3。该酶由一个约等于35 kDa的多肽组成，该多肽结合一个血红素B分子、一个血红素A分子和两个Cu离子。光学光谱表明该蛋白质中存在细胞色素B、细胞色素a3和CuA。氧化蛋白质的定量EPR和穆斯堡尔研究表明存在一个低自旋铁血红素，这是分配给细胞色素B。穆斯堡尔谱研究的还原蛋白质表明存在一个低自旋亚铁血红素，分配给细胞色素B，和一个占主导地位的高自旋亚铁血红素与CO定量反应，产生额外的低自旋亚铁血红素。后一个Fe原子与血红素A结合，被命名为细胞色素a3。氧化蛋白质的EPR谱也揭示了一个CuA型中心的存在，占总Cu的一半。Cu的其余部分似乎以CuB的形式存在，CuB与血红素A磁耦合。细胞色素ba3的氨基酸分析显示存在八至九个组氨酸残基和一个半胱氨酸残基。
We describe an alternate terminal oxidase found in the plasma membrane of Thermus thermophilus and designate it cytochrome ba3. The enzyme consists of a single approximately equal to 35-kDa polypeptide that binds one heme B molecule, one heme A molecule, and two Cu ions. Optical spectra suggest the presence of cytochrome b, cytochrome a3, and CuA in this protein. Quantitative EPR and Mössbauer studies of the oxidized protein indicate the presence of one low-spin ferric heme, which is assigned to cytochrome b. Mössbauer studies of the reduced protein show the presence of one low-spin ferrous heme, assigned to cytochrome b, and a predominant high-spin ferrous heme that reacts quantitatively with CO to yield an additional low-spin ferrous heme. The latter Fe atom is associated with the heme A and is designated cytochrome a3. The EPR spectrum of the oxidized protein also reveals the presence of a CuA-type center that accounts for half the total Cu. The remainder of the Cu would appear to be present as CuB that is magnetically coupled to the heme A. Amino acid analyses of cytochrome ba3 show the presence of eight to nine histidine residues and one cysteine residue.