Oxidative stress defense and deterioration of growth-arrested Escherichia coli cells
Oxidative stress defense and deterioration of growth-arrested Escherichia coli cells
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DOI：
10.1074/jbc.274.37.26027
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发表时间：
1999-09-10
影响因子：
4.8
通讯作者：
Nyström, T
中科院分区：
文献类型：
--
作者：
Dukan, S;Nyström, T
蛋白质羰基化的分析表明，停滞诱导的过氧化氢酶和细胞质超氧化物歧化酶（SOD）在防止大肠杆菌细胞生长停滞期间加速蛋白质氧化中具有作用。与缺乏过氧化氢酶、OxyR或RpoS的细胞相比，在缺乏细胞质SOD的细胞中，大量的蛋白质被羰基化，而缺乏过氧化氢酶、OxyR或RpoS的细胞又表现出比野生型亲本更多的氧化蛋白质。在缺乏细胞质SOD的突变体中停滞期间专门氧化的蛋白质包括GroEL、EF-G和H-NS的酸性同种型，这表明这些突变体在肽延伸和维持蛋白质和DNA结构方面存在问题。这些突变体在停滞期的生存能力也很差。同样地，氧化应激调节剂oxyR的突变缩短了稳定期细胞的寿命，但程度要小得多。缺乏OxyR的细胞的低接种效率是它们不能在标准培养板上生长的结果，除非接种在厌氧条件下或用高浓度的过氧化氢酶进行。相反，缺乏细胞质SOD的细胞似乎在接种前死亡。我们的数据指出了氧化应激防御在停滞生存中的重要性，我们还证明了生长停滞的野生型E。大肠杆菌细胞可以通过省略氧气而显著延长。
Analysis of protein carbonylation demonstrates that the stasis-induced catalases and cytoplasmic superoxide dismutases (SOD) have a role in preventing accelerated protein oxidation during growth arrest of Escherichia coli cells. A larger number of proteins are carbonylated in cells lacking cytoplasmic SOD compared with cells lacking catalases, OxyR, or RpoS which, in turn, exhibit a larger number of oxidized proteins than the wild-type parent. Proteins exclusively oxidized during stasis in mutants lacking cytoplasmic SOD include GroEL, EF-G, and the acidic isoform of H-NS indicating that these mutants experience problems in peptide elongation and maintaining protein and DNA architecture. These mutants also survive stasis poorly. Likewise, but to a much lesser extent, mutations in oxyR, an oxidative stress regulator, shorten the life-span of stationary phase cells. The low plating efficiency of cells lacking OxyR is the result of their inability to grow on standard culture plates unless plating is performed anaerobically or with high concentration of catalase, In contrast, cells lacking cytoplasmic SOD appear to die prior to plating. Our data points to the importance of oxidative stress defense in stasis survival, and we also demonstrate that the lifespan of growth-arrested wild-type E. coli cells can be significantly extended by omitting oxygen.