Group II truncated haemoglobin YjbI prevents reactive oxygen species-induced protein aggregation in <i>Bacillus subtilis</i>
Group II truncated haemoglobin YjbI prevents reactive oxygen species-induced protein aggregation in <i>Bacillus subtilis</i>
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II 组截短血红蛋白 YjbI 防止枯草芽孢杆菌中活性氧诱导的蛋白质聚集
DOI：
10.1101/2021.05.28.446166
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Mihara Hisaaki
中科院分区：
文献类型：
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作者：
Imai Takeshi;Tobe Ryuta;Honda Koji;Tanaka Mai;Kawamoto Jun;Mihara Hisaaki
氧化应激介导的蛋白质氢过氧化物的形成可以诱导肽骨架的不可逆转的断裂和交联型蛋白质聚集体的积累，导致细胞毒性、功能障碍和死亡。然而，细菌如何保护自己免受蛋白质氢过氧化造成的损害尚不清楚。在这里，我们证明了YjbI，一种从枯草芽孢杆菌中截短的第二组血红蛋白，通过其蛋白质氢过氧化物酶样活性来防止细胞表面蛋白质的氧化聚集，该活性从被氧化的蛋白质中去除氢过氧化物基。枯草杆菌yjbI基因的破坏降低了生物膜的拒水性，这与生物膜基质蛋白Tasa的交联聚集有关。YjbI定位于细胞表面或生物膜基质，并且在YjbI中断时，浮游生物生长的细胞对活性氧类生成物的敏感性显著增加，这表明YjbI多向性地保护不稳定的细胞表面蛋白免受氧化损伤。YjbI去除了模型氧化蛋白质底物牛血清白蛋白和生物膜成分TASA中的过氧化氢残留物，防止了体外氧化聚集。此外，YjbI缺陷菌的血液附近的Tyr 63被苯丙氨酸取代，导致其蛋白类过氧化物酶活性丧失，该突变基因不能挽救YjbI缺陷菌株的生物膜拒水性和对次氯酸诱导的氧化胁迫的抗性。这些发现为截短血红蛋白的作用以及从蛋白质中清除过氧化氢在好氧细菌生存中的重要性提供了新的见解。
Oxidative stress-mediated formation of protein hydroperoxides can induce irreversible fragmentation of the peptide backbone and accumulation of cross-linked protein aggregates, leading to cellular toxicity, dysfunction, and death. However, how bacteria protect themselves from damages caused by protein hydroperoxidation is unknown. Here, we show that YjbI, a group II truncated haemoglobin from Bacillus subtilis, prevents oxidative aggregation of cell-surface proteins by its protein hydroperoxide peroxidase-like activity, which removes hydroperoxide groups from oxidised proteins. Disruption of the yjbI gene in B. subtilis lowered biofilm water repellence, which associated with the cross-linked aggregation of the biofilm matrix protein TasA. YjbI was localised to the cell surface or the biofilm matrix, and the sensitivity of planktonically grown cells to generators of reactive oxygen species was significantly increased upon yjbI disruption, suggesting that YjbI pleiotropically protects labile cell-surface proteins from oxidative damage. YjbI removed hydroperoxide residues from the model oxidised protein substrate bovine serum albumin and biofilm component TasA, preventing oxidative aggregation in vitro. Furthermore, the replacement of Tyr 63 near the haem of YjbI with phenylalanine resulted in the loss of its protein peroxidase-like activity, and the mutant gene failed to rescue biofilm water repellency and resistance to oxidative stress induced by hypochlorous acid in the yjbI-deficient strain. These findings provide new insights into the role of truncated haemoglobin and the importance of hydroperoxide removal from proteins in the survival of aerobic bacteria.