Marceau Fanny, Lamothe-Sibold Marlène, Farci Sandrine, Ouchane Soufian, Cassier-Chauvat Corinne, Chauvat Franck
Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
Antioxidants (Basel). 2024 Dec 20;13(12):1577. doi: 10.3390/antiox13121577.
Glutathione S-transferases (GSTs) are evolutionarily conserved enzymes crucial for cell detoxication. They are viewed as having evolved in cyanobacteria, the ancient photosynthetic prokaryotes that colonize our planet and play a crucial role for its biosphere. Xi-class GSTs, characterized by their specific glutathionyl-hydroquinone reductase activity, have been observed in prokaryotes, fungi and plants, but have not yet been studied in cyanobacteria. In this study, we have analyzed the presumptive Xi-class GST, designated as Slr0605, of the unicellular model cyanobacterium PCC 6803. We report that Slr0605 is a homodimeric protein that has genuine glutathionyl-hydroquinone reductase activity. Though Slr0605 is not essential for cell growth under standard photoautotrophic conditions, it plays a prominent role in the protection against not only benzoquinone, but also cobalt-excess stress. Indeed, Slr0605 acts in defense against the cobalt-elicited disturbances of iron homeostasis, iron-sulfur cluster repair, catalase activity and the level of reactive oxygen species, which are all crucial for cell life.
谷胱甘肽S-转移酶（GSTs）是细胞解毒过程中至关重要的进化保守酶。它们被认为是在蓝细菌中进化而来的，蓝细菌是古老的光合原核生物，在地球上广泛存在并对生物圈起着关键作用。Xi类GSTs以其特定的谷胱甘肽基对苯二酚还原酶活性为特征，已在原核生物、真菌和植物中被观察到，但尚未在蓝细菌中进行研究。在本研究中，我们分析了单细胞模式蓝细菌PCC 6803中假定的Xi类GST，命名为Slr0605。我们报告称，Slr0605是一种同二聚体蛋白，具有真正的谷胱甘肽基对苯二酚还原酶活性。虽然在标准光自养条件下，Slr0605对细胞生长并非必需，但它不仅在抵御苯醌方面发挥重要作用，而且在抵御钴过量胁迫方面也发挥着突出作用。事实上，Slr0605在防御钴引发的铁稳态紊乱、铁硫簇修复、过氧化氢酶活性以及活性氧水平方面发挥作用，而这些对于细胞生命都是至关重要的。
