Molecular and biochemical analysis of the novel molybdenum-enzyme mARC

在这个项目中，我们希望揭示植物类MARC蛋白的功能和重要性，其中两个由拟南芥基因组编码。mARC（mitochondrial amidoxime reducing component）是我们最近在哺乳动物中发现的一种新的偕胺肟酶。我们的初步工作表明，来自猪肝线粒体外膜的mARC是真核生物中已知的最小的钼酶，并且其活性严格依赖于钼辅因子。mARC似乎代表了一种新型的腺嘌呤蛋白，因为它仅在与其他蛋白复合时才获得酶活性，而迄今为止已知的所有其他腺嘌呤酶在单个多肽链内包含活性所需的所有辅基。我们将研究植物类MARC蛋白的酶和结构特征，并研究这些蛋白是否与其他蛋白形成氧化还原复合物。我们打算分析植物mARC同源物是否位于线粒体外膜，以及它们是否具有N-还原能力。最后，我们想描绘的mARC样蛋白发挥的代谢作用，并阐明其对植物的重要性。

In this project we want to unveil the function and importance of plant mARC-like proteins, of which two are encoded by the genome of Arabidopsis thaliana. mARC (mitochondrial amidoxime reducing component) is a novel molybdenum-enzyme that we have very recently discovered in mammals. Our preliminary work showed that mARC from the outer membrane of pig liver mitochondria is the smallest molybdenum-enyzme known in eukaryotes and that its activity is strictly dependent on molybdenum cofactor. mARC seems to represent a new type of molybdenum-proteins as it gains enzymatic activity only in complex with other proteins, while all other molybdenum-enzymes known to date comprise all prosthetic groups required for activity within a single polypetide chain. We will study the enzymatic and structural characteristics of plant mARC-like proteins and examine whether these proteins are associated with other proteins forming a redox complex. We intend to analyze whether the plant mARC homologs are located at the outer membrane of mitochondria and whether they have N-reducing capacity. Finally we want to delineate the metabolic role played by mARC-like proteins and clarify their importance for the plant.