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首页> 外文期刊>Infection and immunity >An NADPH Quinone Reductase of Helicobacter pylori Plays an Important Role in Oxidative Stress Resistance and Host Colonization
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An NADPH Quinone Reductase of Helicobacter pylori Plays an Important Role in Oxidative Stress Resistance and Host Colonization

机译：幽门螺杆菌的NADPH醌还原酶在抗氧化应激和寄主定植中起重要作用

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Oxidative stress resistance is one of the key properties that enable pathogenic bacteria to survive the toxic reactive oxygen species released by the host. In a previous study characterizing oxidative stress resistance mutants of Helicobacter pylori, a novel potential antioxidant protein (MdaB) was identified by the observation that the expression of this protein was significantly upregulated to compensate for the loss of other major antioxidant components. In this study, we characterized an H. pylori mdaB mutant and the MdaB protein. While the wild-type strain can tolerate 10% oxygen for growth, the growth of the mdaB mutant was significantly inhibited by this oxygen condition. The mdaB mutant is also more sensitive to H2O2, organic hydroperoxides, and the superoxide-generating agent paraquat. Although the wild-type strain can survive more than 10 h of air exposure, exposure of the mutant strain to air for 8 h resulted in recovery of no viable cells. The oxidative stress sensitivity of the mdaB mutant resulted in a deficiency in the ability to colonize mouse stomachs. H. pylori was recovered from 10 of 11 mouse stomachs inoculated with the wild-type strain, with about 5,000 to 45,000 CFU/g of stomach. However, only 3 of 12 mice that were inoculated with the mdaB mutant strain were found to harbor any H. pylori, and these 3 contained less than 2,000 CFU/g of stomach. A His-tagged MdaB protein was purified and characterized. It was shown to be a flavoprotein that catalyzes two-electron transfer from NAD(P)H to quinones. It reduces both ubiquinones and menaquinones with similar efficiencies and preferably uses NADPH as an electron donor. We propose that the physiological function of the H. pylori MdaB protein is that of an NADPH quinone reductase that plays an important role in managing oxidative stress and contributes to successful colonization of the host.
机译：抗氧化应激是使病原细菌能够生存于宿主释放的有毒活性氧中的关键特性之一。在先前的表征幽门螺杆菌氧化应激抗性突变体的研究中，通过观察到该蛋白的表达被显着上调以补偿其他主要蛋白的丢失，发现了一种潜在的新型抗氧化蛋白（MdaB）。抗氧化剂成分。在这项研究中，我们表征了 H。幽门螺杆菌mdaB 突变体和MdaB蛋白。虽然野生型菌株可以忍受10％的氧气生长，但 mdaB 突变体的生长却受到这种氧气条件的抑制。 mdaB 突变体对H 2 O 2 ，有机氢过氧化物和超氧化物产生剂百草枯也更敏感。尽管野生型菌株可以在暴露于空气的情况下存活超过10小时，但是将突变菌株暴露在空气中8小时导致没有存活细胞的恢复。 mdaB 突变体的氧化应激敏感性导致定居小鼠胃的能力不足。 H。从接种了野生型菌株的11个小鼠胃中的10个中回收了幽门螺杆菌，每克胃约有5,000至45,000 CFU。但是，在接种了 mdaB 突变株的12只小鼠中，只有3只带有 H。幽门螺杆菌，而这3种食物每克胃中的胆固醇含量不到2,000 CFU。纯化并鉴定了带有His标签的MdaB蛋白。它被证明是一种黄素蛋白，可催化从NAD（P）H到醌的两电子转移。它以相似的效率还原泛醌和甲萘醌，并且优选使用NADPH作为电子供体。我们提出 H的生理功能。幽门螺杆菌MdaB蛋白是NADPH醌还原酶的一种，在控制氧化应激中起重要作用，并有助于宿主成功定殖。

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