Cytochrome bcc-aa3 Oxidase Supercomplexes in the Aerobic Respiratory Chain of Streptomyces coelicolor A3(2)
Cytochrome bcc-aa3 Oxidase Supercomplexes in the Aerobic Respiratory Chain of Streptomyces coelicolor A3(2)
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DOI：
10.1159/000496390
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发表时间：
2018-01-01
影响因子：
1.2
通讯作者：
Sawers, R. Gary
中科院分区：
文献类型：
--
作者：
Falke, Doerte;Fischer, Marco;Sawers, R. Gary
天蓝色链霉菌A3（2）是一种专性好氧、氧化酶阳性和丝状土壤细菌，在其呼吸链中缺乏可溶性细胞色素c，而是具有膜相关的二血红素c型细胞色素QcrC。这需要形成复合物以允许细胞色素bcc和aa 3氧化酶呼吸复合物之间的电子转移。将遗传互补研究与凝胶内细胞色素氧化酶活性染色相结合，我们证明了染色体上完整的qcrCAB-ctaCDFE基因位点（分别编码bcc和aa 3复合物）是在qcr-cta缺失突变体的孢子和菌丝中表现出细胞色素氧化酶活性所必需的。蓝色-天然-PAGE鉴定了约270 kDa的细胞色素aa 3氧化酶复合物，其催化氧依赖性二氨基联苯胺氧化而不需要外源提供的细胞色素c，表明与QcrC相关。此外，更高分子量的复合物被确定后，添加可溶性细胞色素c，这表明超复合物是不稳定的，很容易解离成亚复合物缺乏QcrC。免疫学和质谱分析的活性，高分子量氧化酶的复合物分离的明确的天然PAGE确定的BCC复合物和AA 3氧化酶的关键亚基，支持超复合物的形成。我们的数据还表明，细胞色素B Qcr B的bcc复合物是不太丰富的孢子相比，菌丝体。(C)2019 S. Karger AG，巴塞尔
Streptomyces coelicolor A3(2), an obligately aerobic, oxidase-positive, and filamentous soil bacterium, lacks a soluble cytochrome c in its respiratory chain, having instead a membrane-associated diheme c-type cytochrome, QcrC. This necessitates complex formation to allow electron transfer between the cytochrome bcc and aa3 oxidase respiratory complexes. Combining genetic complementation studies with in-gel cytochrome oxidase activity staining, we demonstrate that the complete qcrCAB-ctaCDFE gene locus on the chromosome, encoding, respectively, the bcc and aa3 complexes, is required to manifest a cytochrome oxidase enzyme activity in both spores and mycelium of a qcr-cta deletion mutant. Blue-native-PAGE identified a cytochrome aa3 oxidase complex of approximately 270 kDa, which catalyzed oxygen-dependent diaminobenzidine oxidation without the requirement for exogenously supplied cytochrome c, indicating association with QcrC. Furthermore, higher molecular mass complexes were identified upon addition of soluble cytochrome c, suggesting the supercomplex is unstable and readily dissociates into subcomplexes lacking QcrC. Immunological and mass spectrometric analyses of active, high-molecular mass oxidase-containing complexes separated by clear-native PAGE identified key subunits of both the bcc complex and the aa3 oxidase, supporting supercomplex formation. Our data also indicate that the cytochrome b QcrB of the bcc complex is less abundant in spores compared with mycelium. (C) 2019 S. Karger AG, Basel