Optical and resonance Raman spectroscopy of the heme groups of the quinol-oxidizing cytochrome aa3 of Bacillus subtilis.
Optical and resonance Raman spectroscopy of the heme groups of the quinol-oxidizing cytochrome aa3 of Bacillus subtilis.
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DOI：
10.1021/bi00156a027
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发表时间：
1992-10
期刊：
影响因子：
2.9
通讯作者：
M. Lauraeus;Mårten Wikström;C. Varotsis;M. Tecklenburg;Gerald T. Babcock
中科院分区：
文献类型：
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作者：
M. Lauraeus;Mårten Wikström;C. Varotsis;M. Tecklenburg;Gerald T. Babcock
枯草芽孢杆菌的细胞色素aa 3型末端醌醇氧化酶催化双氧四电子还原成水。它类似于aa 3型细胞色素c氧化酶，使用血红素A作为其活性位点发色团，但缺乏CuA中心和线粒体酶的细胞色素c氧化活性。我们用光学和共振拉曼光谱研究了B。subtilis oxidase的详细信息。相对于大多数其他aa 3型氧化酶，还原的减去氧化酶的α-带吸收最大值向蓝色移动5-7 nm，因此，我们将芽孢杆菌酶命名为细胞色素aa 3 -600。移位的光谱不能归因于低自旋血红素的甲酰基与其环境之间的氢键强度的改变，因为在aa 3 -600中分配给该模式的拉曼线具有与大多数其他aa 3型氧化酶中的低自旋血红素甲酰基模式相同的频率和共振增强程度。拉曼模式出现在194和214 cm-1的aa 3 -600，而一个单一的频带在约214 cm-1被指定为其他aa 3型氧化酶的铁-组氨酸伸缩。这两种模式的发生可能的解释进行了讨论。比较aa 3 -600和牛心细胞色素c氧化酶不同氧化态下的甲酰基和乙烯基模式以及血红素骨架振动模式，显示出很强的相似性，这表明这些氧化酶中血红素环境的基本特征是保守的。
The cytochrome aa3-type terminal quinol oxidase of Bacillus subtilis catalyzes the four-electron reduction of dioxygen to water. It resembles the aa3-type cytochrome-c oxidase in using heme A as its active-site chromophores but lacks the CuA center and the cytochrome-c oxidizing activity of the mitochondrial enzyme. We have used optical and resonance Raman spectroscopies to study the B. subtilis oxidase in detail. The alpha-band absorption maximum of the reduced minus oxidized enzyme is shifted by 5-7 nm to the blue relative to most other aa3-type oxidases, and accordingly, we designate the Bacillus enzyme as cytochrome aa3-600. The shifted optical spectrum cannot be ascribed to an alteration in the strength of the hydrogen bond between the formyl group of the low-spin heme and its environment, as the Raman line assigned to this mode in aa3-600 has the same frequency and degree of resonance enhancement as the low-spin heme a formyl mode in most other aa3-type oxidases. Raman modes arise at 194 and 214 cm-1 in aa3-600, whereas a single band at about 214 cm-1 is assigned to the iron-histidine stretch for the other aa3-type oxidases. Possible explanations for the occurrence of these two modes are discussed. Comparison of formyl and vinyl modes and heme skeletal vibrational modes in different oxidation states of aa3-600 and of beef heart cytochrome-c oxidase shows a strong similarity, which suggests conservation of essential features of the heme environments in these oxidases.