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Oxygen detoxification by dienoyl-CoA oxidase involving flavin/disulfide cofactors.
Molecular Microbiology ( IF 3.6 ) Pub Date : 2020-02-21 , DOI: 10.1111/mmi.14493
Georg Schmid 1 , Marieke Scheffen 1 , Max Willistein 1 , Matthias Boll 1
Affiliation  

Class I benzoyl‐CoA reductases (BCRs) are oxygen‐sensitive key enzymes in the degradation of monocyclic aromatic compounds in anaerobic prokaryotes. They catalyze the ATP‐dependent reductive dearomatization of their substrate to cyclohexa‐1,5‐diene‐1‐carboxyl‐CoA (1,5‐dienoyl‐CoA). An aromatizing 1,5‐dienoyl‐CoA oxidase (DCO) activity has been proposed to protect BCRs from oxidative damage, however, the gene and its product involved have not been identified, yet. Here, we heterologously produced a DCO from the hyperthermophilic euryarchaeon Ferroglobus placidus that coupled the oxidation of two 1,5‐dienoyl‐CoA to benzoyl‐CoA to the reduction of O2 to water at 80°C. DCO showed similarities to members of the old yellow enzyme family and contained FMN, FAD and an FeS cluster as cofactors. The O2‐dependent activation of inactive, reduced DCO is assigned to a redox thiol switch at E o′ = −3 mV. We propose a catalytic cycle in which the active site FMN/disulfide redox centers are reduced by two 1,5‐dienoyl‐CoA (reductive half‐cycle), followed by two consecutive two‐electron transfer steps to molecular oxygen via peroxy‐ and hydroxyflavin intermediates yielding water (oxidative half‐cycle). This work identified the enzyme involved in a unique oxygen detoxification process for an oxygen‐sensitive catabolic enzyme.

中文翻译:

通过涉及黄素/二硫化物辅因子的二烯丙基-CoA氧化酶进行的氧气解毒。

I类苯甲酰辅酶A还原酶(BCR)是厌氧原核生物中单环芳族化合物降解中对氧敏感的关键酶。它们催化将其底物的ATP依赖性还原脱芳香化为环己1,5-二烯-1-羧基-CoA(1,5-二壬基-CoA)。有人提出了一种芳香化的1,5-二烯丙基-CoA氧化酶(DCO)活性来保护BCR不受氧化损伤,但是,尚未发现该基因及其产物。在这里,我们从超嗜热性球菌费酸中异源产生了DCO,该DCO将两个1,5-二烯酰基-CoA氧化为苯甲酰基-CoA的氧化与O 2的还原相结合在80°C下加水。DCO显示与旧的黄色酶家族成员相似,并且包含FMN,FAD和FeS簇作为辅助因子。不活跃的,还原的DCO的依赖于O 2的活化被分配给E o '= -3 mV的氧化还原硫醇开关。我们提出了一个催化循环,其中活性位点FMN /二硫键的氧化还原中心被两个1,5-二烯丙基-CoA(还原性半循环)还原,随后是两个连续的两电子通过过氧和羟基黄素转移到分子氧的步骤产生水的中间体(氧化半循环)。这项工作确定了一种对氧敏感的分解代谢酶独特的氧解毒过程的酶。
更新日期:2020-02-21
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