General and oxidative stress responses in Bacillus subtilis: Cloning, expression, and mutation of the alkyl hydroperoxide reductase operon
General and oxidative stress responses in Bacillus subtilis: Cloning, expression, and mutation of the alkyl hydroperoxide reductase operon
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DOI：
10.1128/jb.178.22.6571-6578.1996
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发表时间：
1996-11-01
影响因子：
3.2
通讯作者：
Hecker, M
中科院分区：
文献类型：
--
作者：
Antelmann, H;Engelmann, S;Hecker, M
枯草芽孢杆菌烷基过氧化氢还原酶的AhpC亚基被鉴定为响应于热或盐胁迫或在生物体进入稳定期后诱导的一般胁迫蛋白。克隆编码AhpC和AhpF两个亚基的ahp操纵子，并将其定位在gntRKPZ操纵子和bglA基因座之间，二维凝胶分析揭示了在受到氧化应激的细胞中AhpC和AhpF的特别强的诱导，转录研究表明，在热或盐胁迫或葡萄糖饥饿后ahp mRNA的诱导增加3至4倍，氧化胁迫诱导增加20倍，从而证实了AhpC和AhpF的蛋白诱导数据，与野生型相比，ahpC突变体对过氧化氢具有抗性，这是因为过氧化物调节子（N.布萨特湖Chen和J. D. Helmann，J. Bacteriol. 178：6579-6586，1996），但在指数生长期间对氢过氧化枯烯（CHP）更敏感。相反，静止期野生型和ahpC突变体细胞显示出对用ImM CHP处理的完全抗性。此外，发现σ（B）突变体在营养生长期间和静止期对CHP极其敏感，这表明σ（B）依赖性一般应激蛋白参与保护细胞免受氧化应激。
The AhpC subunit of the Bacillus subtilis alkyl hydroperoxide reductase was identified as a general stress protein induced in response to heat or salt stress or after entry of the organism into the stationary phase, The ahp operon, encoding the two subunits AhpC and AhpF, was cloned and localized between the gntRKPZ operon and the bglA locus, Two-dimensional gel analyses revealed an especially strong induction of AhpC and AhpF in cells subjected to oxidative stress, Transcriptional studies showed a 3- to 4-fold induction of ahp mRNA after heat or salt stress or starvation for glucose and a 20-fold induction by oxidative stress, thus confirming the protein induction data for AhpC and AhpF, Stress induction occurred at a sigma(A)-dependent promoter that overlaps with operator sites similar to the per box, Compared with the wild type, the ahpC mutant was resistant to hydrogen peroxide because of the derepression of the peroxide regulon (N. Bsat, L. Chen, and J. D. Helmann, J. Bacteriol. 178:6579-6586, 1996) but more sensitive to cumene hydroperoxide (CHP) during exponential growth, In contrast, stationary-phase wild-type and ahpC mutant cells displayed complete resistance to treatment with 1 mM CHP, Moreover, a sigma(B) mutant was found to be extremely sensitive to CHP during vegetative growth and in stationary phase, which indicates that sigma(B)-dependent general stress proteins are involved in the protection of cells against oxidative stress.