Escherichia coli di-iron YtfE protein is necessary for the repair of stress-damaged iron-sulfur clusters
Escherichia coli di-iron YtfE protein is necessary for the repair of stress-damaged iron-sulfur clusters
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DOI：
10.1074/jbc.m610656200
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发表时间：
2007-04-06
影响因子：
4.8
通讯作者：
Saraiva, Ligia M.
中科院分区：
文献类型：
--
作者：
Justino, Marta C.;Almeida, Claudia C.;Saraiva, Ligia M.
DNA微阵列实验表明，暴露于一氧化氮后，大肠杆菌ytfE基因的表达高度增加。我们还报道了ytfE的缺失显著改变了E.大肠杆菌，产生一个菌株，具有增强的亚硝化胁迫的敏感性和缺陷的几个铁-硫含蛋白的活性。在这项工作中，它表明，E。大肠杆菌ytfE赋予针对氧化应激的保护。此外，我们发现，在没有ytfE的情况下，由暴露于过氧化氢和一氧化氮应激引起的乌头酸酶B和乌头酸酶A的[ 4Fe-4S]（2+）簇的损伤以更高的速率发生。ytfE无效突变也消除了乌头酸酶和天冬氨酸酶活性的恢复，这在野生型E.大肠杆菌中的蛋白质。值得注意的是，在向突变体细胞提取物中加入纯化的holo-YtfE蛋白后，天冬氨酸酶和乌头酸酶的酶活性完全恢复，并且速率与野生型菌株相似.我们得出结论，YtfE是关键的修复铁硫簇损伤的氧化和亚硝化应激条件。
DNA microarray experiments showed that the expression of the Escherichia coli ytfE gene is highly increased upon exposure to nitric oxide. We also reported that deletion of ytfE significantly alters the phenotype of E. coli, generating a strain with enhanced susceptibility to nitrosative stress and defective in the activity of several iron- sulfur- containing proteins. In this work, it is shown that the E. coli ytfE confers protection against oxidative stress. Furthermore, we found that the damage of the [ 4Fe-4S](2+) clusters of aconitase B and fumarase A caused by exposure to hydrogen peroxide and nitric oxide stress occurs at higher rates in the absence of ytfE. The ytfE null mutation also abolished the recovery of aconitase and fumarase activities, which is observed in wild type E. coli once the stress is scavenged. Notably, upon the addition of purified holo- YtfE protein to the mutant cell extracts, the enzymatic activities of fumarase and aconitase are fully recovered and at rates similar to the wild type strain. We concluded that YtfE is critical for the repair of iron- sulfur clusters damaged by oxidative and nitrosative stress conditions.