Hydrogen-oxidizing electron transport components in the hyperthermophilic archaebacterium Pyrodictium brockii
Hydrogen-oxidizing electron transport components in the hyperthermophilic archaebacterium Pyrodictium brockii
复制标题
超嗜热古细菌 Pyrodictium brockii 中的氢氧化电子传递成分
作者：
T. Pihl;L. Black;B. Schulman;R. Maier
极端嗜热古细菌Pyrodictium brockii在105摄氏度下通过称为氢硫自养的代谢形式最佳生长，其特征在于H2被SO氧化以产生ATP和H2S。紫外线照射的膜不能进行硫的氢依赖性还原。然而，活性可以通过添加泛醌Q10或泛醌Q6的UV损伤的膜恢复。通过薄层色谱法从布氏原杆菌的膜中纯化出一种具有与Q6类似的薄层色谱迁移特性的醌，但核磁共振分析未能证实其为泛醌。布氏青霉醌能够恢复紫外辐照膜的氢依赖性硫还原。氢还原减空气氧化膜上的吸收差光谱显示的吸收峰的C型细胞色素的特征。分别在553、522和421 nm处具有α、β和γ峰的C-型细胞色素用0.5% Triton X-100从膜中溶解。吡啶铁血红素光谱证实其身份作为C型细胞色素，和血红素染色的十二烷基硫酸钠凝胶上加载的膜显示一个单一的血红素含13至14 kDa的组件。对泛醌类似物2-正庚基-4-羟基喹啉-N-氧化物的研究表明，布氏原杆菌醌相对于c型细胞色素位于电子传递链的底物侧。严格厌氧的，大概是原始的P. brockii电子传递链的这些第一个特征表明，氢化酶在相对高的氧化还原电位下工作，并且H2氧化链更接近于好氧真细菌H2氧化细菌的H2氧化链，而不是厌氧菌或超嗜热的激烈火球菌的H2代谢系统。
The hyperthermophilic archaebacterium Pyrodictium brockii grows optimally at 105 degrees C by a form of metabolism known as hydrogen-sulfur autotrophy, which is characterized by the oxidation of H2 by S0 to produce ATP and H2S. UV-irradiated membranes were not able to carry out the hydrogen-dependent reduction of sulfur. However, the activity could be restored by the addition of ubiquinone Q10 or ubiquinone Q6 to the UV-damaged membranes. A quinone with thin-layer chromatography migration properties similar to those of Q6 was purified by thin-layer chromatography from membranes of P. brockii, but nuclear magnetic resonance analysis failed to confirm its identity as a ubiquinone. P. brockii quinone was capable of restoring hydrogen-dependent sulfur reduction to UV-irradiated membranes. Hydrogen-reduced-minus-air-oxidized absorption difference spectra on membranes revealed absorption peaks characteristic of c-type cytochromes. A c-type cytochrome with alpha, beta, and gamma peaks at 553, 522, and 421 nm, respectively, was solubilized from membranes with 0.5% Triton X-100. Pyridine ferrohemochrome spectra confirmed its identity as a c-type cytochrome, and heme staining of membranes loaded on sodium dodecyl sulfate gels revealed a single heme-containing component of 13 to 14 kDa. Studies with the ubiquinone analog 2-n-heptyl-4-hydroxyquinoline-N-oxide demonstrated that the P. brockii quinone is located on the substrate side of the electron transport chain with respect to the c-type cytochrome. These first characterizations of the strictly anaerobic, presumably primitive P. brockii electron transport chain suggest that the hydrogenase operates at a relatively high redox potential and that the H2-oxidizing chain more closely resembles those of aerobic eubacterial H2-oxidizing bacteria than those of the H2-metabolizing systems of anaerobes or the hyperthermophile Pyrococcus furiosus.
强烈火球菌铁氧还蛋白中新型铁硫簇的光谱表征。
DOI：
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发表时间：
1990
期刊：
The Journal of biological chemistry
影响因子：
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作者：
Conover,RC;Kowal,AT;Fu,WG;Park,JB;Aono,S;Adams,MW;Johnson,MK
通讯作者：
Johnson,MK