Glutathione is the major thiol-based antioxidant in a wide variety of biological systems, ranging from bacteria to eukaryotes. As a redox couple, consisting of reduced glutathione (GSH) and its oxidized form, glutathione disulfide (GSSG), it is crucial for the maintenance of the cellular redox balance. Glutathione transport out of and into cellular compartments and the extracellular space is a determinant of the thiol-disulfide redox state of the organelles and bodily fluids in question, but is currently not well understood. Here we use the genetically-encoded, glutathione-measuring redox probe Grx1-roGFP2 to comprehensively elucidate the import of extracellular glutathione into the cytoplasm of the model organism Escherichia coli. The elimination of only two ATP-Binding Cassette (ABC) transporter systems, Gsi and Opp, completely abrogates glutathione import into E. coli’s cytoplasm, both in its reduced and oxidized form. The lack of only one of them, Gsi, completely prevents import of GSSG, while the lack of the other, Opp, substantially retards the uptake of reduced glutathione (GSH).

中文翻译：

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ABC 转运蛋白 Opp 进口还原型谷胱甘肽，而 Gsi 进口大肠杆菌中的二硫化谷胱甘肽


谷胱甘肽是各种生物系统中主要的巯基基抗氧化剂，从细菌到真核生物。作为由还原型谷胱甘肽 （GSH） 及其氧化形式谷胱甘肽二硫化物 （GSSG） 组成的氧化还原对，它对于维持细胞氧化还原平衡至关重要。谷胱甘肽转运出和进入细胞区室和细胞外空间是所讨论的细胞器和体液的巯基-二硫键氧化还原状态的决定因素，但目前尚不清楚。在这里，我们使用基因编码的谷胱甘肽测量氧化还原探针 Grx1-roGFP2 来全面阐明细胞外谷胱甘肽进入模式生物大肠杆菌细胞质的过程。仅消除两个 ATP 结合盒 （ABC） 转运蛋白系统 Gsi 和 Opp，完全消除了谷胱甘肽以还原和氧化形式输入到大肠杆菌细胞质中的谷胱甘肽。仅缺乏其中一种 GSI 完全阻止了 GSSG 的输入，而另一种缺乏 Opp 则大大延缓了还原型谷胱甘肽 （GSH） 的摄取。