UMR 1136 INRA Nancy University, Interactions Arbres-Microorganismes, IFR 110 EFABA, Faculté des Sciences, 54506 Vandœuvre-lès-Nancy, France.
FEBS Lett. 2011 Apr 6;585(7):1077-81. doi: 10.1016/j.febslet.2011.03.006. Epub 2011 Mar 6.
Trx-z is a chloroplastic thioredoxin, exhibiting a usual WCGPC active site, but whose biochemical properties are unknown. We demonstrate here that Trx-z supports the activity of several plastidial antioxidant enzymes, such as thiol-peroxidases and methionine sulfoxide reductases, using electrons provided by ferredoxin-thioredoxin reductase. Its disulfide reductase activity requires the presence of both active site cysteines forming a catalytic disulfide bridge with a midpoint redox potential of -251 mV at pH7. These in vitro biochemical data suggest that, besides its decisive role in the regulation of plastidial transcription, Trx-z might also be involved in stress response.
Trx-z 是一种质体硫氧还蛋白，具有常见的 WCGPC 活性位点，但生化性质未知。我们在这里证明，Trx-z 利用铁氧还蛋白-硫氧还蛋白还原酶提供的电子，支持几种质体抗氧化酶，如硫氧还蛋白过氧化物酶和蛋氨酸亚砜还原酶的活性。其二硫键还原酶活性需要两个活性位点半胱氨酸的存在，它们形成一个催化二硫键桥，在 pH7 时中点氧化还原电位为-251 mV。这些体外生化数据表明，除了在调节质体转录中起决定性作用外，Trx-z 可能还参与应激反应。
