The mitochondrial monothiol glutaredoxin S15 is essential for iron-sulfur protein maturation in Arabidopsis thaliana
The mitochondrial monothiol glutaredoxin S15 is essential for iron-sulfur protein maturation in Arabidopsis thaliana
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DOI：
10.1073/pnas.1510835112
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发表时间：
2015-11-03
影响因子：
11.1
通讯作者：
Meyer, Andreas J.
中科院分区：
文献类型：
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作者：
Moseler, Anna;Aller, Isabel;Meyer, Andreas J.
铁硫簇（ISC）是许多参与电子转移和代谢反应的蛋白质的古老且重要的辅助因子。在拟南芥中，细胞质、质体和线粒体中铁硫蛋白的成熟存在三种途径。我们通过遗传、生理和生化方法相结合，从功能上表征了线粒体谷氧还蛋白 S15 (GRXS15) 在含有乌头酸酶的 ISC 生物合成中的作用。两个拟南芥 T-DNA 插入突变体被鉴定为具有早期胚胎致死表型的无效突变体，可以被 GRXS15 拯救。此外，我们表明重组 GRXS15 能够协调和转移 ISC，并且这种协调依赖于还原型谷胱甘肽 (GSH)。我们发现拟南芥 GRXS15 能够基于酵母 Delta grx5 突变体的 ISC 蛋白组装受到干扰来弥补生长缺陷。 GRXS15 对相关非植物蛋白晶体结构的建模突出显示了突变后会削弱 GSH 和随后的 ISC 协调以及拯救酵母突变体的能力的氨基酸残基。当用于植物互补时，其中一种突变体 GRXS15(K83/A) 会导致严重的发育迟缓，乌头酸酶活性显着降低约 65%。这些结果表明线粒体 GRXS15 是拟南芥中的必需蛋白，是铁硫蛋白完全活性所必需的。
The iron-sulfur cluster (ISC) is an ancient and essential cofactor of many proteins involved in electron transfer and metabolic reactions. In Arabidopsis, three pathways exist for the maturation of iron-sulfur proteins in the cytosol, plastids, and mitochondria. We functionally characterized the role of mitochondrial glutaredoxin S15 (GRXS15) in biogenesis of ISC containing aconitase through a combination of genetic, physiological, and biochemical approaches. Two Arabidopsis T-DNA insertion mutants were identified as null mutants with early embryonic lethal phenotypes that could be rescued by GRXS15. Furthermore, we showed that recombinant GRXS15 is able to coordinate and transfer an ISC and that this coordination depends on reduced glutathione (GSH). We found the Arabidopsis GRXS15 able to complement growth defects based on disturbed ISC protein assembly of a yeast Delta grx5 mutant. Modeling of GRXS15 onto the crystal structures of related nonplant proteins highlighted amino acid residues that after mutation diminished GSH and subsequently ISC coordination, as well as the ability to rescue the yeast mutant. When used for plant complementation, one of these mutant variants, GRXS15(K83/A), led to severe developmental delay and a pronounced decrease in aconitase activity by approximately 65%. These results indicate that mitochondrial GRXS15 is an essential protein in Arabidopsis, required for full activity of iron-sulfur proteins.