Redox Protein OsaR (PA0056) Regulates dsbM and the Oxidative Stress Response in Pseudomonas aeruginosa
Redox Protein OsaR (PA0056) Regulates dsbM and the Oxidative Stress Response in Pseudomonas aeruginosa
复制标题
氧化还原蛋白 OsaR (PA0056) 调节铜绿假单胞菌中的 dsbM 和氧化应激反应
DOI：
10.1128/aac.01771-20
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发表时间：
2021-03-01
影响因子：
4.9
通讯作者：
Qiao, Mingqiang
中科院分区：
文献类型：
--
作者：
Liu, Yujie;Ma, Yibing;Qiao, Mingqiang
细菌已经进化出独特的分子机制作为对氧化应激的防御。氧化应激反应的最重要的调节剂已被发现是OxyR。然而，OxyR上游调控的分子细节在很大程度上仍然未知，需要进一步研究。在这里，我们表征的氧化应激和抗生素耐受性调节剂，OsaR（PA 0056），铜绿假单胞菌产生的。敲除osaR增加了细菌对氨基糖苷类和β-内酰胺类抗生素以及过氧化氢的耐受性。在osaR突变体中，oxyR调节子基因oxyR、katAB和ahpBCF的表达增加。然而，OsaR蛋白不通过直接结合其启动子来调节oxyR调节子基因。PA 0055，osaR，PA 0057，和dsbM是在同一个基因簇，我们提供的证据表明，这些基因的表达参与氧化耐受性的OsaR之间的基因间区域的结合控制osaR和PA 0057，其中包含两个不同的启动子。该基因簇也通过间接作用由PA 0055调节。我们进一步发现，OsaR在氧化应激时形成分子内二硫键，导致其DNA结合亲和力的变化。综上所述，我们的结果表明，OsaR被氧化应激灭活，并在铜绿假单胞菌对氨基糖苷类和β-内酰胺类抗生素的耐受性中发挥作用。
Bacteria have evolved distinct molecular mechanisms as a defense against oxidative stress. The foremost regulator of the oxidative stress response has been found to be OxyR. However, the molecular details of regulation upstream of OxyR remain largely unknown and need further investigation. Here, we characterize an oxidative stress and antibiotic tolerance regulator, OsaR (PA0056), produced by Pseudomonas aeruginosa. Knocking out of osaR increased bacterial tolerance to aminoglycoside and beta-lactam antibiotics, as well as to hydrogen peroxide. Expression of the oxyR regulon genes oxyR, katAB, and ahpBCF was increased in the osaR mutant. However, the OsaR protein does not regulate the oxyR regulon genes through direct binding to their promoters. PA0055, osaR, PA0057, and dsbM are in the same gene cluster, and we provide evidence that expression of those genes involved in oxidant tolerance is controlled by the binding of OsaR to the intergenic region between osaR and PA0057, which contain two divergent promoters. The gene cluster is also regulated by PA0055 via an indirect effect. We further discovered that OsaR formed intramolecular disulfide bonds when exposed to oxidative stress, resulting in a change of its DNA binding affinity. Taken together, our results indicate that OsaR is inactivated by oxidative stress and plays a role in the tolerance of P. aeruginosa to aminoglycoside and beta-lactam antibiotics.