M Sudharsan, N Rajendra Prasad, Chakraborty Anindita, Rajendrasozhan Saravanan
Department of Biochemistry and Biotechnology, Annamalai University, Annamalainagar, 608 002, Tamilnadu, India.
UGC-DAE Consortium for Scientific Research, Kolkata Centre, 700098, West Bengal, India.
J Proteomics. 2022 Sep 15;267:104697. doi: 10.1016/j.jprot.2022.104697. Epub 2022 Aug 20.
This study explains the importance of cellular redox system in preserving the proteome of the radioresistant Deinococcus radiodurans. The thioredoxin reductase (TrxR) redox system was inhibited by ebselen (10 μM), and then the bacterium was exposed to 4 kGy of ionizing radiation. The differentially expressed proteins were analyzed using label-free quantitative (LFQ) proteomics. The 4 kGy radiation treatment increases the expression of stress response proteins like osmotically inducible protein OsmC, catalase, and metallophosphoesterase compared to control. Ebselen plus radiation treatment augments oxidoreductases proteins in D. radiodurans. Further, the proteins involved in glycolysis, tricarboxylic acetic acid (TCA) and proteins like proteases, peptidase, and peptide transporters were significantly decreased in the ebselen plus radiation group compared to radiation treated group. Further, ebselen plus radiation treatment increases the ATP-binding cassette (ABC) transporters involved in the efflux of toxic chemicals and nutrient uptake and the stress response related membrane protein like S-layer homology domain-containing protein in D. radiodurans. Thus, the results show that the altered redox status via inhibition of TrxR redox system significantly affects the expression of essential cellular proteins for the survival. The cellular content of D. radiodurans may be used to handle redox imbalances in the normal cells during cancer radiotherapy. SIGNIFICANCE: Deinococcus radiodurans is a popular radioresistance organism with efficient antioxidant systems and DNA repair mechanisms. There are many antioxidant systems and small molecules that responsible for its resistance. The importance of thiol based antioxidant systems in its resistance property has not fully studied yet. Thioredoxin reductase is an important disulfide containing protein that involved in maintaining redox homeostasis. The TrxR inhibition affects the cell survival and synthesis of molecules against ionizing radiation. In this study we are reporting the effects of TrxR inhibitor on proteome of D. radiodurans upon ionizing radiation. This study reveals the significance of TrxR antioxidant system on the proteome of D. radiodurans. The inhibition of TrxR antioxidant system and the subsequent disturbances in the proteome content makes the organism vulnerable to oxidative stress.
本研究解释了细胞氧化还原系统在保护抗辐射细菌耐辐射奇异球菌蛋白质组方面的重要性。用依布硒啉（10 μM）抑制硫氧还蛋白还原酶（TrxR）氧化还原系统，然后将该细菌暴露于4千戈瑞的电离辐射下。使用无标记定量（LFQ）蛋白质组学分析差异表达的蛋白质。与对照组相比，4千戈瑞的辐射处理增加了应激反应蛋白的表达，如渗透诱导蛋白OsmC、过氧化氢酶和金属磷酸酯酶。依布硒啉加辐射处理增强了耐辐射奇异球菌中氧化还原酶蛋白的表达。此外，与辐射处理组相比，依布硒啉加辐射处理组中参与糖酵解、三羧酸循环（TCA）的蛋白质以及蛋白酶、肽酶和肽转运蛋白等蛋白质显著减少。此外，依布硒啉加辐射处理增加了参与有毒化学物质外排和营养物质摄取的ATP结合盒（ABC）转运蛋白以及耐辐射奇异球菌中与应激反应相关的膜蛋白，如含S层同源结构域的蛋白。因此，结果表明，通过抑制TrxR氧化还原系统改变氧化还原状态会显著影响细胞生存所必需的蛋白质的表达。耐辐射奇异球菌的细胞成分可用于在癌症放疗期间处理正常细胞中的氧化还原失衡。意义：耐辐射奇异球菌是一种具有高效抗氧化系统和DNA修复机制的著名抗辐射生物。有许多抗氧化系统和小分子负责其抗性。基于硫醇的抗氧化系统在其抗性特性中的重要性尚未得到充分研究。硫氧还蛋白还原酶是一种重要的含二硫键蛋白，参与维持氧化还原稳态。TrxR抑制会影响细胞存活以及抗电离辐射分子的合成。在本研究中，我们报告了TrxR抑制剂对耐辐射奇异球菌在电离辐射后蛋白质组的影响。本研究揭示了TrxR抗氧化系统对耐辐射奇异球菌蛋白质组的重要性。TrxR抗氧化系统的抑制以及随后蛋白质组含量的紊乱使该生物体易受氧化应激的影响。
