The aerobic electron flux is deficient in fumarate respiration of a strict anaerobe Bacteroides thetaiotaomicron.
The aerobic electron flux is deficient in fumarate respiration of a strict anaerobe Bacteroides thetaiotaomicron.
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严格厌氧菌多形拟杆菌的富马酸呼吸需要有氧电子通量不足。
DOI：
10.1016/j.bbrc.2022.05.017
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发表时间：
2022
影响因子：
3.1
通讯作者：
Zheng Lu
中科院分区：
文献类型：
--
作者：
Luyou Lin;Zheng Lu
为什么氧气会阻止严格厌氧细菌的生长是一个长期存在的问题，但答案仍不清楚。研究证实，含有铁硫簇（[4Fe-4S]）的脱水酶-富马酸酶在暴露于肠道专性厌氧菌拟杆菌(Bacteroides thetaiotaomicron，B。叫多);这阻断了富马酸呼吸，这是厌氧菌必不可少的能量产生途径。在这里，我们在b中取代了[4Fe-4S]依赖性富马酸酶。taiotaomicron与来自me的无铁同工酶。杆菌(Ec-FumC)。结果表明，Ec-FumC在b中成功地发挥了富马酸酶的催化作用。taiotaomicron作为表达Ec-FumC的真菌突变株，在厌氧生长条件下表现出琥珀酸生成能力。Ec-FumC具有抗氧性，在曝气后仍能产生富马酸酯；然而,B。表达Ec-FumC的taiotaomic突变体在暴露于空气中时不能将富马酸转化为琥珀酸盐。野生b型倒置膜泡的生化分析。纳米显微镜证实了从NADH到富马酸盐的电子通量在有空气的情况下比在没有氧气的情况下效率低。我们的研究结果表明，厌氧富马酸呼吸可能由于电子耗散在专性厌氧通气时瘫痪。
Why oxygen ceases the growth of strictly anaerobic bacteria is a longstanding question, yet the answer remains unclear. Studies have confirmed that the dehydratase—fumarase containing an iron-sulfur cluster ([4Fe–4S]) is inactivated upon exposure to oxygen in the intestinal obligate anaerobe,Bacteroides thetaiotaomicron(B. thetaiotaomicron); this blocks fumarate respiration, which is the essential energy-producing pathway in anaerobes. Here, we substituted the [4Fe–4S]-dependent fumarase inB. thetaiotaomicronwith an iron-free isozyme fromE. coli(Ec-FumC). Results show that Ec-FumC successfully performed the catalytic function of fumarase inB. thetaiotaomicron, as thefum-mutant strain that expressed Ec-FumC exhibited succinate-producing ability under anaerobic growth conditions. Ec-FumC is oxygen-resistant and remains active to produce fumarate upon aeration; however,B. thetaiotaomicronmutant that expressed Ec-FumC did not convert fumarate to succinate during air exposure. Biochemical assays of inverted membrane vesicles from wild-typeB. thetaiotaomicronconfirmed that the electron flux from NADH to fumarate was less efficient in the presence of air as compared to that without oxygen. Our findings suggest that the anaerobic fumarate respiration might be paralyzed due to electron dissipations upon aeration of the obligate anaerobe.
影响因子：
15.9
作者：
Khademian M;Imlay JA
通讯作者：
Imlay JA