An iron-regulated alkyl hydroperoxide reductase (AhpC) confers aerotolerance and oxidative stress resistance to the microaerophilic pathogen Campylobacter jejuni
An iron-regulated alkyl hydroperoxide reductase (AhpC) confers aerotolerance and oxidative stress resistance to the microaerophilic pathogen Campylobacter jejuni
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DOI：
10.1128/jb.181.16.4798-4804.1999
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发表时间：
1999-08-01
影响因子：
3.2
通讯作者：
Penn, CW
中科院分区：
文献类型：
--
作者：
Baillon, MLA;van Vliet, AHM;Penn, CW
像空肠弯曲杆菌这样的微生物在传播或感染过程中必须抵抗氧化应激。在铁限制条件下，C，空肠81116的生长显著增加了26和55 kDa两种多肽的表达，通过n端氨基酸测序鉴定这两种蛋白均参与氧化应激防御。编码空肠C. 26-kDa蛋白的基因克隆结果表明，编码的蛋白与烷基氢过氧化物还原酶（AhpC）的小亚基具有显著的同源性，AhpC的上游区域编码一个不同的铁氧还蛋白（fdxA）同源序列，而下游序列含有flhB和motB同源序列。报道基因研究表明，铁对ahpC和katA的调控是在转录水平上实现的。ahpF编码烷基氢过氧化物还原酶的大亚基。ahpC基因的插入诱变导致对过氧化氢异丙苯引起的氧化应激和暴露于大气氧的敏感性增加，而对过氧化氢的抗性不受影响。C，空肠ahpC蛋白是这种微嗜气病原体在氧化和有氧应激中生存能力的重要决定因素。
Microaerophiles like Campylobacter jejuni must resist oxidative stresses during transmission or Infection. Growth of C, jejuni 81116 under iron limitation greatly increased the expression of two polypeptides of 26 and 55 kDa, The identification of these proteins by N-terminal amino acid sequencing showed both to be involved in the defense against oxidative stress. The 55-kDa polypeptide was identical to C. jejuni catalase (KatA), whereas the N terminus of the 26-kDa polypeptide was homologous to a 26-kDa Helicobacter pylori protein, The gene encoding the C. jejuni 26-kDa protein was cloned, and the encoded protein showed significant homology to the small subunit of alkyl hydroperoxide reductase (AhpC), The upstream region of ahpC encoded a divergent ferredoxin (fdxA) homolog, whereas downstream sequences contained flhB and motB homologs, which are involved in flagellar motility, There was no evidence for an adjacent homolog of ahpF, encoding the large subunit of alkyl hydroperoxide reductase, Reporter gene studies showed that iron regulation of ahpC and katA is achieved at the transcriptional level. Insertional mutagenesis of the ahpC gene resulted in an increased sensitivity to oxidative stresses caused by cumene hydroperoxide and exposure to atmospheric oxygen, while resistance to hydrogen peroxide was not affected, The C, jejuni AhpC protein is an important determinant of the ability of this microaerophilic pathogen to survive oxidative and aerobic stress.