Overexpression of fetA (ybbL) and fetB (ybbM), Encoding an Iron Exporter, Enhances Resistance to Oxidative Stress in Escherichia coli
Overexpression of fetA (ybbL) and fetB (ybbM), Encoding an Iron Exporter, Enhances Resistance to Oxidative Stress in Escherichia coli
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DOI：
10.1128/aem.02322-13
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发表时间：
2013-12-01
影响因子：
4.4
通讯作者：
Papoutsakis, Eleftherios T.
中科院分区：
文献类型：
--
作者：
Nicolaou, Sergios A.;Fast, Alan G.;Papoutsakis, Eleftherios T.
活性氧是由氧化还原反应和H2O2与铁的芬顿反应产生的，其产生导致严重DNA、蛋白质和脂质损伤的羟基自由基。我们筛选了大肠杆菌基因组文库，以确定一个片段，含有cueR，ybbJ，qmcA，ybbL，和ybbM，增强抗H2O2胁迫。我们报告说，三角洲ybbL和三角洲ybbM菌株更容易受到H2O2应力比亲本菌株和ybbL和ybbM过表达克服H2O2敏感性。预测的ybbL和ybbM基因编码的ATP结合盒金属转运蛋白，我们证明，YbbM是一种膜蛋白。我们研究了各种金属，以确定铁作为这种转运蛋白的可能底物。我们建议将基因命名为fetA和fetB（用于铁转运），并将基因产物命名为FetA和FetB。FetAB允许在铁的存在下增加对氧化应激的抵抗力，揭示了在铁稳态中的作用。我们表明，铁超载加上H2O2压力废除fetA和fetB过表达的亲本菌株和三角洲毛皮应变，铁的吸收是失调。此外，我们利用全细胞电子顺磁共振显示，在三角洲毛皮应变细胞内铁水平下降了37%的fetA和fetB过表达。结合，这些研究结果表明，fetA和fetB编码的铁输出蛋白具有增强对H2O2介导的氧化应激的抵抗力的作用，并可以在铁过载的条件下最大限度地减少氧化应激，并表明FetAB促进铁稳态，以减少氧化应激。
Reactive oxygen species are generated by redox reactions and the Fenton reaction of H2O2 and iron that generates the hydroxyl radical that causes severe DNA, protein, and lipid damage. We screened Escherichia coli genomic libraries to identify a fragment, containing cueR, ybbJ, qmcA, ybbL, and ybbM, which enhanced resistance to H2O2 stress. We report that the Delta ybbL and Delta ybbM strains are more susceptible to H2O2 stress than the parent strain and that ybbL and ybbM overexpression overcomes H2O2 sensitivity. The ybbL and ybbM genes are predicted to code for an ATP-binding cassette metal transporter, and we demonstrate that YbbM is a membrane protein. We investigated various metals to identify iron as the likely substrate of this transporter. We propose the gene names fetA and fetB (for Fe transport) and the gene product names FetA and FetB. FetAB allows for increased resistance to oxidative stress in the presence of iron, revealing a role in iron homeostasis. We show that iron overload coupled with H2O2 stress is abrogated by fetA and fetB overexpression in the parent strain and in the Delta fur strain, where iron uptake is deregulated. Furthermore, we utilized whole-cell electron paramagnetic resonance to show that intracellular iron levels in the Delta fur strain are decreased by 37% by fetA and fetB overexpression. Combined, these findings show that fetA and fetB encode an iron exporter that has a role in enhancing resistance to H2O2-mediated oxidative stress and can minimize oxidative stress under conditions of iron overload and suggest that FetAB facilitates iron homeostasis to decrease oxidative stress.