Soluble and membrane‐bound paramagnetic centers in Methanobacterium Bryantii
Soluble and membrane‐bound paramagnetic centers in Methanobacterium Bryantii
复制标题
布氏甲烷杆菌中可溶性和膜结合的顺磁中心
DOI：
10.1016/0014-5793(80)81188-4
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发表时间：
1980
期刊：
影响因子：
3.5
通讯作者：
J. Lancaster
中科院分区：
文献类型：
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作者：
J. Lancaster
产甲烷细菌是一组独特的生物体（表示为古细菌）的成员，它们显然与原核生物和真核生物只有很远的关系[1，2]。产甲烷菌的特征在于仅通过Hz还原CO2以产生甲烷而自养生长的能力。已分离出几种产甲烷菌特有的电子载体和“因子”，包括辅酶Fd 2 [3，4]，FM 2 [5]和F4%[5]，以及辅酶M（2巯基乙磺酸[6，4]）。虽然已经揭示了FJ 2和辅酶M在CO2还原中的作用[4，7]，但实际上对通过从Hz到CO2的电子传递的能量转导机制一无所知。通过使用低温EPR光谱，我在这里报告了氧化和还原顺磁物质的存在。M. bryantii。具体而言，观察到的信号是：1。可溶性部分中氧化的铁-硫中心（HiPIP型Fe，-&* 或Fes-Ss*）的典型信号，可能是氢化酶。2.一种非常不寻常的膜结合菱形高温氧化物种，其所有三个eg值均显著高于自由电子值，这可能是一种新型簇合物或铁以外的过渡金属，可能是镍（见第4节）。
The methanogenic bacteria are members of a unique group of organisms (denoted Archaebacteria) which are apparently only distantly related to prokaryotes and eukaryotes [1, 2]. Methanogens are characterized by the ability to grow autotrophically solely by the reduction of COZ by Hz to produce methane. Several electron carriers and ‘factors’ unique to methanogens have been isolated, including coenzymes Fd2,,[3, 4], FM2 [5] and F4%[5], as well as coenzyme M (Zmercaptoethanesulfonic acid [6, 4]). While some light has been shed on the roles of FJ2,, and coenzyme M in COZ reduction [4, 7], virtually nothing is known about the mechanism (s) of energy transduction via electron transport from Hz to COZ. By using low-temperature EPR spectroscopy I report here the presence of oxidized and reduced paramagnetic species,. both soluble and membranebound, in M. bryantii. Specifically, the signals observed are:1. A signal typical of an oxidized iron-sulfur center (either HiPIP-type Fe,-&* or Fes-Ss*) in the soluble fraction, possibly hydrogenase. 2. A very unusual membrane-bound rhombic hightemperature oxidized species with all threeg-values significantly above the free-electron value, which may be either a new type of cluster or a transition metal other than iron, possibly nickel (see section 4).