Hemerythrins in the microaerophilic bacterium Campylobacter jejuni help protect key iron-sulphur cluster enzymes from oxidative damage.
Hemerythrins in the microaerophilic bacterium Campylobacter jejuni help protect key iron-sulphur cluster enzymes from oxidative damage.
复制标题
DOI：
10.1111/1462-2920.12341
复制
发表时间：
2014-04
影响因子：
5.1
通讯作者：
Kelly DJ
中科院分区：
文献类型：
--
作者：
Kendall JJ;Barrero-Tobon AM;Hendrixson DR;Kelly DJ
嗜气微细菌适应低氧环境，但其在空气中生长被抑制的机制尚不清楚。微嗜气病原菌空肠弯曲杆菌的柠檬酸循环具有潜在的脆弱性，因为它使用含有不稳定（4Fe-4S）中心的丙酮酸和2-氧葡萄糖酸受体氧化还原酶（Por和Oor）。在这里，我们发现这两种酶在细胞暴露于完全有氧环境后迅速失活。我们研究了可能保护酶活性的机制，并确定了氰菊酯HerA （Cj0241）的作用。herA突变体在暴露于21% （v/v）的氧气后表现出有氧生长缺陷和贫酶和贫酶活性降低。在氧损伤后，观察到这些活性缓慢的厌氧恢复，但在野生型和herA菌株中速率相似，这表明herA的作用是防止Fe-S簇损伤，而不是促进修复。另一种氰菊酯（HerB; Cj1224）也有保护作用。纯化后的HerA和HerB表现出μ-氧桥接双铁含氰菊酯典型的光学吸收、配体结合和共振拉曼光谱。我们认为，氧不稳定性和贫氧和贫氧修复不良是空肠梭菌嗜微气的主要原因；氰菊酯有助于防止微生物或氧瞬态酶损伤。
Microaerophilic bacteria are adapted to low oxygen environments, but the mechanisms by which their growth in air is inhibited are not well understood. The citric acid cycle in the microaerophilic pathogen Campylobacter jejuni is potentially vulnerable, as it employs pyruvate and 2-oxoglutarate:acceptor oxidoreductases (Por and Oor), which contain labile (4Fe-4S) centres. Here, we show that both enzymes are rapidly inactivated after exposure of cells to a fully aerobic environment. We investigated the mechanisms that might protect enzyme activity and identify a role for the hemerythrin HerA (Cj0241). A herA mutant exhibits an aerobic growth defect and reduced Por and Oor activities after exposure to 21% (v/v) oxygen. Slow anaerobic recovery of these activities after oxygen damage was observed, but at similar rates in both wild-type and herA strains, suggesting the role of HerA is to prevent Fe-S cluster damage, rather than promote repair. Another hemerythrin (HerB; Cj1224) also plays a protective role. Purified HerA and HerB exhibited optical absorption, ligand binding and resonance Raman spectra typical of μ-oxo-bridged di-iron containing hemerythrins. We conclude that oxygen lability and poor repair of Por and Oor are major contributors to microaerophily in C. jejuni; hemerythrins help prevent enzyme damage microaerobically or during oxygen transients.
登录
查看更多内容
影响因子：
3.6
作者：
Jang S;Imlay JA
通讯作者：
Imlay JA
DOI：
10.1073/pnas.151243198
发表时间：
2001-07-03
影响因子：
11.1
作者：
Gralnick, J;Downs, D
通讯作者：
Downs, D
影响因子：
3.2
作者：
Hughes, NJ;Clayton, CL;Kelly, DJ
通讯作者：
Kelly, DJ
影响因子：
48
作者：
Gibson, Daniel G.;Young, Lei;Smith, Hamilton O.
通讯作者：
Smith, Hamilton O.
影响因子：
3.2
作者：
Hügler, M;Wirsen, CO;Sievert, SM
通讯作者：
Sievert, SM