Purification and characterization of the alternative nitrogenase from the photosynthetic bacterium Rhodospirillum rubrum
Purification and characterization of the alternative nitrogenase from the photosynthetic bacterium Rhodospirillum rubrum
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DOI：
10.1128/jb.178.5.1445-1450.1996
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发表时间：
1996-03-01
影响因子：
3.2
通讯作者：
Ludden, PW
中科院分区：
文献类型：
--
作者：
Davis, R;Lehman, L;Ludden, PW
来自光合细菌红色红螺菌的 nifH 突变体的替代固氮酶已被纯化和表征。二氮酶蛋白 (ANF1) 在明显的 α(2) beta(2) gamma(2) 结构中含有三个亚基，并且含有 Fe，但不含 Mo 或 V。使用 N-甲基甲酰胺从替代二氮酶蛋白中提取了能够激活 Azotobacter vinelandii 的脱辅基二氮酶（缺乏 FeMo 辅因子）的因子。二固氮酶蛋白的电子顺磁共振(EPR)信号不是含钼或含钒二固氮酶的EPR信号的特征。替代二固氮酶还原酶 (ANF2) 被纯化为含有 Fe4S4 簇的 α(2) 二聚体，并表现出二固氮酶还原酶的 EPR 谱特征。该酶复合物可以很好地将质子还原为 H-2，但很难将 N-2 还原为铵。乙炔被还原成乙烯和乙烷的混合物。
The alternative nitrogenase from a nifH mutant of the photosynthetic bacterium Rhodospirillum rubrum has been purified and characterized. The dinitrogenase protein (ANF1) contains three subunits in an apparent alpha(2) beta(2) gamma(2) structure and contains Fe but no Mo or V. A factor capable of activating apo-dinitrogenase (lacking the FeMo cofactor) from Azotobacter vinelandii was extracted from the alternative dinitrogenase protein with N-methylformamide. The electron paramagnetic resonance (EPR) signal of the dinitrogenase protein is not characteristic of the EPR signals of molybdenum- or vanadium-containing dinitrogenases. The alternative dinitrogenase reductase (ANF2) was purified as an alpha(2) dimer containing an Fe4S4 cluster and exhibited an EPR spectrum characteristic of dinitrogenase reductases. The enzyme complex reduces protons to H-2 very well but reduces N-2 to ammonium poorly. Acetylene is reduced to a mixture of ethylene and ethane.