EPR spectroscopic characterization of an ‘iron only⌉ nitrogenase S = 3/2 spectrum of component 1 isolated from Rhodobacter capsulatus
EPR spectroscopic characterization of an ‘iron only⌉ nitrogenase S = 3/2 spectrum of component 1 isolated from Rhodobacter capsulatus
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从荚膜红细菌中分离出的“仅铁”固氮酶 S = 3/2 组分 1 的 EPR 光谱表征
DOI：
10.1016/0014-5793(92)80472-s
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发表时间：
1992
期刊：
影响因子：
3.5
通讯作者：
W. Hagen
中科院分区：
文献类型：
--
作者：
A. Müller;K. Schneider;K. Knüttel;W. Hagen
从一株HDK缺失突变株中分离到的荚膜红杆菌（Rhodobacter capsulatus）的替代性固氮酶已被纯化至接近均一，并被鉴定为“仅含铁”的固氮酶。连二亚硫酸盐还原的组分1（“FeFe蛋白”）或该酶显示出由两个组分组成的EPR光谱：在g = 1.93处的次要S = 12信号和在g = 5.44处的接近化学计量强度的非常典型的S = 32信号。这一共振非常接近于S = 32系统的两个内双重态子光谱重合时的最高可能值（g= 5.46）或最大菱方性（E/D= 0.33）。偏离轴对称性（增加E/D）与不同（Mo、V、Fe）固氮酶的稳定性、活性和底物选择性相关。
The alternative nitrogenase ofRhodobacter capsulatus, isolated from anifHDKdeletion mutant, has been purified to near homogeneity and identified as an ‘iron only’ nitrogenase. The dithionite‐reduced component 1 (‘FeFe protein’) or this enzyme showed an EPR spectrum consisting of two components: a minorS= 12 signal atg= 1.93 and a very characteristicS= 32 signal of near‐stoichiometric intensity atg= 5.44. This resonance is very close to the highest possiblegvalue (g= 5.46) for the coinciding two intradoublet subspectra of anS= 32 system or maximal rhombicity (E/D= 0.33)). The deviation from axial symmetry (increasingE/D) correlates with the stability, activity and substrate selectivity of the different (Mo, V, Fe) nitrogenases.