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首页> 外文期刊>Journal of bacteriology >Hydrogen-Dependent Nitrogenase Activity and ATP Formation in Rhizobium japonicum Bacteroids
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Hydrogen-Dependent Nitrogenase Activity and ATP Formation in Rhizobium japonicum Bacteroids

机译：jailogium japonicum菌株中的氢依赖性氮酶活性和ATP形成

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Rhizobium japonicum 122 DES bacteroids from soybean nodules possess an active H2-oxidizing system that recycles all of the H2 lost through nitrogenase-dependent H2 evolution. The addition of 72 μM H2 to suspensions of bacteroids increased O2 uptake 300% and the rate of C2H2 reduction 300 to 500%. The optimal partial pressure of O2 was increased, and the partial pressure of O2 range for C2H2 reduction was extended by adding H2. A supply of succinate to bacteroids resulted in effects similar to those obtained by adding H2. Both H2 and succinate provided respiratory protection for the N2-fixing system in bacteroids. The oxidation of H2 by bacteroids increased the steady-state pool of ATP by 20 to 40%. In the presence of 50 mM iodoacetate, which caused much greater inhibition of endogenous respiration than of H2 oxidation, the addition of H2 increased the steady-state pool of ATP in bacteroids by 500%. Inhibitor evidence and an absolute requirement for O2 indicated that the H2-stimulated ATP synthesis occurred through oxidative phosphorylation. In the presence of 50 mM iodoacetate, H2-dependent ATP synthesis occurred at a rate sufficient to support nitrogenase activity. The addition of H2 to H2 uptake-negative strains of R. japonicum had no effect on ATP formation or C2H2 reduction. It is concluded that the H2-oxidizing system in H2 uptake-positive bacteroids benefits the N2-fixing process by providing respiratory protection of the O2-labile nitrogenase proteins and generating ATP to support maximal rates of C2H2 reduction by oxidation of the H2 produced from the nitrogenase system.
机译：来自大豆结节的japonicum 122 des Bactops具有活性H 2 - 氧化系统，可通过氮酶依赖性H丢失所有H 2 2 演进。将72μmH 2 加入菌株的悬浮液，增加O 2 摄取300％和c 2 h 2 < /亚>减少300至500％。 o 2 的最佳部分压力增加，C 2 h 2 2 2的分压。 >通过添加H 2 来延长减少。琥珀酸盐的琥珀酸供应导致与通过加入H 2 获得的效果类似的效果。 H 2 和琥珀酸琥珀酸盐为杆状体中的n 2 -fixing系统提供了呼吸保护。通过组织将H 2 的氧化增加了20％至40％的稳态池。在50mM的碘乙酸盐存在下，这引起了比H 2 氧化更大的抑制内源性呼吸，加入H 2 增加了稳态ATP池菌株500％。抑制剂证据和O 2 的绝对要求表明H 2 -stimulated的ATP合成通过氧化磷酸化发生。在50mM碘乙酸酯的存在下，H 2 - 依赖性ATP合成以足以支持氮酶活性的速率发生。将H 2 加入H 2 摄取阴性菌株的 r。 japonicum 对ATP形成或C 2 h 2 减少影响。得出结论，H 2 氧化系统在H 2 摄取阳性杆状膜通过提供呼吸保护，有利于n 2 -fixing过程O 2 -Labile氮酶蛋白并产生ATP以支持通过氧化H 2的C 2 H 2的最大速率由氮酶系统制成。

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