Australian Research Council Centre of Excellence in Plant Energy Biology, M316, University of Western Australia, Crawley, Western Australia 6009, Australia.
Plant Physiol. 2010 Feb;152(2):747-61. doi: 10.1104/pp.109.147942. Epub 2009 Dec 14.
Understanding the metal ion content of plant mitochondria and metal ion interactions with the proteome are vital for insights into both normal respiratory function and the process of protein damage during oxidative stress. We have analyzed the metal content of isolated Arabidopsis (Arabidopsis thaliana) mitochondria, revealing a 26:8:6:1 molar ratio for iron:zinc:copper:manganese and trace amounts of cobalt and molybdenum. We show that selective changes occur in mitochondrial copper and iron content following in vivo and in vitro oxidative stresses. Immobilized metal affinity chromatography charged with Cu(2+), Zn(2+), and Co(2+) was used to identify over 100 mitochondrial proteins with metal-binding properties. There were strong correlations between the sets of immobilized metal affinity chromatography-interacting proteins, proteins predicted to contain metal-binding motifs, and protein sets known to be oxidized or degraded during abiotic stress. Mitochondrial respiratory chain pathways and matrix enzymes varied widely in their susceptibility to metal-induced loss of function, showing the selectivity of the process. A detailed study of oxidized residues and predicted metal interaction sites in the tricarboxylic acid cycle enzyme aconitase identified selective oxidation of residues in the active site and showed an approach for broader screening of functionally significant oxidation events in the mitochondrial proteome.
了解植物线粒体中的金属离子含量以及金属离子与蛋白质组的相互作用，对于深入了解正常呼吸功能以及氧化应激过程中蛋白质损伤的机制至关重要。我们分析了分离的拟南芥（Arabidopsis thaliana）线粒体的金属含量，发现铁：锌：铜：锰的摩尔比为 26:8:6:1，并且还存在痕量的钴和钼。我们表明，在线粒体铜和铁含量在体内和体外氧化应激后会发生选择性变化。用固定化金属亲和色谱法（immobilized metal affinity chromatography）负载 Cu(2+)、Zn(2+) 和 Co(2+)，鉴定出超过 100 种具有金属结合特性的线粒体蛋白。固定化金属亲和色谱相互作用蛋白组、预测含有金属结合模体的蛋白组和在非生物胁迫期间已知发生氧化或降解的蛋白组之间存在很强的相关性。线粒体呼吸链途径和基质酶在其对金属诱导功能丧失的敏感性方面差异很大，显示出该过程的选择性。对三羧酸循环酶 aconitase 中氧化残基和预测的金属相互作用位点的详细研究，确定了活性位点中残基的选择性氧化，并为更广泛地筛选线粒体蛋白质组中功能重要的氧化事件提供了一种方法。
