Metal Selectivity of Manganese Superoxide Dismutase

锰超氧化物歧化酶的金属选择性

• 批准号: 7148885
• 负责人: Mei Yang
• 金额: $ 1.85万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2006-08-06
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7148885
• 关键词: Saccharomyces cerevisiae; active sites; atomic absorption spectrometry; binding sites; enzyme activity; eukaryote; gene deletion mutation; gene expression; genetic transcription; intermolecular interaction; intracellular; ions; iron metabolism; manganese; microarray technology; mitochondria; mutant; postdoctoral investigator; superoxide dismutase

DESCRIPTION (provided by applicant): The overall goal of this proposal is to understand the in vivo metal ion selectivity for eukaryotic manganese superoxide dismutase (SOD2). SOD2 is a critical anti-oxidant enzyme of the mitochondria. The enzyme is active when manganese is bound to the catalytic site, but in vivo interactions with other metals such as iron have not been explored. We have previously shown that SOD2 activity is impaired in mtm1delta mutant strains of yeast that accumulate high mitochondrial iron. We will now test whether iron can inhibit SOD2 activity in vivo and whether Mtm1p facilitates selectivity for the correct metal. We shall (Aim 1) determine whether iron can occupy the metal binding site of SOD2 and inactivate the enzyme in vivo. The activity of SOD2 and metal content of the enzyme purified to homogeneity will be assessed as a function of intracellular manganese and iron availability. Secondly (Aim 2), we shall test whether the high mitochondrial iron ofmtml mutants is responsible for loss of SOD2 activity by genetically and nutritionally controlling intracellular iron levels. In Aim 3, transcriptional genome-wide microarray analysis will be utilized to determine the complex cellular response to loss of Mtmlp and pathways that lead to inactivation of SOD2. Together, these studies are designed to advance our understanding of how eukaryotic SOD2 obtains its manganese co-factor in vivo.

描述（由申请人提供）： 该提案的总体目标是了解真核锰超氧化物歧化酶（SOD2）的体内金属离子选择性。 SOD2 是线粒体的重要抗氧化酶。当锰与催化位点结合时，该酶具有活性，但与铁等其他金属的体内相互作用尚未被探索。我们之前已经表明，在积累高线粒体铁的 mtm1delta 酵母突变株中，SOD2 活性受损。我们现在将测试铁是否可以抑制体内 SOD2 活性以及 Mtm1p 是否有助于对正确金属的选择性。我们将（目标 1）确定铁是否可以占据 SOD2 的金属结合位点并使体内酶失活。 SOD2 的活性和纯化至同质的酶的金属含量将作为细胞内锰和铁可用性的函数进行评估。其次（目标 2），我们将通过遗传和营养控制细胞内铁水平来测试 mtml 突变体的高线粒体铁是否导致 SOD2 活性丧失。在目标 3 中，将利用转录全基因组微阵列分析来确定对 Mtmlp 丢失的复杂细胞反应以及导致 SOD2 失活的途径。总之，这些研究旨在加深我们对真核 SOD2 如何在体内获得其锰辅助因子的理解。