Manganese import is a key element of the OxyR response to hydrogen peroxide in Escherichia coli.
Manganese import is a key element of the OxyR response to hydrogen peroxide in Escherichia coli.
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DOI：
10.1111/j.1365-2958.2009.06699.x
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发表时间：
2009-05
影响因子：
3.6
通讯作者：
Imlay JA
中科院分区：
文献类型：
--
作者：
Anjem A;Varghese S;Imlay JA
在常规生长条件下，很少有锰输入到大肠杆菌中：输入系统弱表达，锰含量低，锰依赖性酶没有正确金属化。缺乏MntH的突变体以野生型的速度生长，表明锰没有发挥关键作用。然而，MntH支持缺铁细胞的生长，这表明锰可以替代铁激活至少一些金属酶。当细胞受到过氧化氢应激时，MntH也被强烈诱导。这种适应是必要的，因为E. mntH基因缺失后，大肠杆菌不能耐受过氧化氢胁迫。其他工作者已经观察到锰提高了各种微生物耐受氧化应激的能力，并且流行的假设是锰通过化学清除过氧化氢和/或超氧化物来实现这一点。我们发现，锰不能通过清除过氧化物来保护过氧化物应激细胞。相反，锰的有益作用与其金属化单核酶的能力相关。由于负载铁的酶易受芬顿反应的影响，因此锰的取代可以防止蛋白质损伤。因此，在H2 O2胁迫期间，不能输入锰和/或不能螯合铁的突变体遭受高速率的蛋白质氧化。
Very little manganese is imported into Escherichia coli under routine growth conditions: the import system is weakly expressed, the manganese content is low, and a manganese-dependent enzyme is not correctly metallated. Mutants that lack MntH, the importer, grow at wild-type rates, indicating that manganese plays no critical role. However, MntH supports the growth of iron-deficient cells, suggesting that manganese can substitute for iron in activating at least some metalloenzymes. MntH is also strongly induced when cells are stressed by hydrogen peroxide. This adaptation is essential, as E. coli cannot tolerate peroxide stress if mntH is deleted. Other workers have observed that manganese improves the ability of a variety of microbes to tolerate oxidative stress, and the prevailing hypothesis is that manganese does so by chemically scavenging hydrogen peroxide and/or superoxide. We found that manganese does not protect peroxide-stressed cells by scavenging peroxide. Instead, the beneficial effects of manganese correlate with its ability to metallate mononuclear enzymes. Because iron-loaded enzymes are vulnerable to the Fenton reaction, the substitution of manganese may prevent protein damage. Accordingly, during H2O2 stress, mutants that cannot import manganese and/or are unable to sequester iron suffer high rates of protein oxidation.
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影响因子：
3.2
作者：
ARCHIBALD, FS;FRIDOVICH, I
通讯作者：
FRIDOVICH, I
影响因子：
4.8
作者：
Henle, ES;Han, ZX;Linn, S
通讯作者：
Linn, S
影响因子：
3.9
作者：
Al-Maghrebi, M;Fridovich, I;Benov, L
通讯作者：
Benov, L
DOI：
10.2741/adams
发表时间：
2001-08-01
期刊：
FRONTIERS IN BIOSCIENCE
影响因子：
--
作者：
Adams, S;Green, P;Leeuwenburgh, C
通讯作者：
Leeuwenburgh, C
DOI：
10.1073/pnas.120163297
发表时间：
2000-06-06
影响因子：
11.1
作者：
Datsenko, KA;Wanner, BL
通讯作者：
Wanner, BL