Characterization of the amidoxime reducing components ARC1 and ARC2 from Arabidopsis thaliana
Characterization of the amidoxime reducing components ARC1 and ARC2 from Arabidopsis thaliana
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DOI：
10.1111/febs.16450
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发表时间：
2022-04
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影响因子：
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通讯作者：
Ludmila Maiber;Anna Koprivova;Daniel Bender;S. Kopriva;Katrin Fischer-Schrader
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作者：
Ludmila Maiber;Anna Koprivova;Daniel Bender;S. Kopriva;Katrin Fischer-Schrader
在真核生物中已知五种钼依赖性酶。虽然其中四个几十年来一直在研究中，但最近发现的（线粒体）偕胺肟还原组分（（m）ARC）仅在哺乳动物和绿色藻类莱茵衣藻中发现。虽然哺乳动物mARC已被证明参与各种信号传导途径，但衣原体ARC被证明是一氧化氮（NO）形成亚硝酸盐还原酶。与哺乳动物相似，高等植物也有两种ARC蛋白。为了检测植物ARC是否具有与C. reinhardtii中，我们分析了来自模式植物拟南芥的酶。来自拟南芥的ARC 1和ARC 2都可以还原N-羟基化化合物，而只有ARC 2可以证明亚硝酸盐还原形成NO。寻找生理电子供体，我们发现两种ARC酶通过细胞色素b5还原酶和细胞色素b5接受来自NADH的电子，但只有ARC 2能够接受来自硝酸还原酶的电子。此外，弧缺陷突变体植物在生长和亚硝酸盐依赖的NO形成方面与野生型植物相似。总之，我们的结果没有证实拟南芥的ARC 1或ARC 2参与生理相关的亚硝酸盐依赖的NO形成的假设。相反，我们的数据表明，ARC 1和ARC 2在高等植物中具有不同的，但未知的生理作用。
Five molybdenum‐dependent enzymes are known in eukaryotes. While four of them are under investigation since decades, the most recently discovered, (mitochondrial) amidoxime reducing component ((m)ARC), has only been characterized in mammals and the green algae Chlamydomonas reinhardtii. While mammalian mARCs have been shown to be involved in various signalling pathways, Chlamydomonas ARC was shown to be a nitric oxide (NO)‐forming nitrite reductase. Similar to mammals, higher plants possess two ARC proteins. To test whether plant ARCs have a similar function in NO production to the function they have in C. reinhardtii, we analysed the enzymes from the model plant Arabidopsis thaliana. Both ARC1 and ARC2 from Arabidopsis could reduce N‐hydroxylated compounds, while nitrite reduction to form NO could only be demonstrated for ARC2. Searching for physiological electron donors, we found that both ARC enzymes accept electrons from NADH via cytochrome b5 reductase and cytochrome b5, but only ARC2 is able to accept electrons from nitrate reductase at all. Furthermore, arc‐deficient mutant plants were similar to wildtype plants regarding growth and also nitrite‐dependent NO‐formation. Altogether, our results did not confirm the hypothesis that either ARC1 or ARC2 from Arabidopsis are involved in physiologically relevant nitrite‐dependent NO‐formation. In contrast, our data suggest that ARC1 and ARC2 have distinct, yet unknown physiological roles in higher plants.