Studies of Biological Iron Oxidation

生物铁氧化的研究

• 批准号: 0000989
• 负责人: Shannon Stahl
• 金额: $ 3.5万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-15 至 2001-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0000989&HistoricalAwards=false
• 关键词: Studies; Biological; Iron; Oxidation

0000989StahlTransition metals play an important role in cellular redox reactions. Iron, the most abundant transition metal ion in biology, poses a two-fold challenge: the reduced state can be toxic and the oxidized state is very insoluble under physiological conditions. Consequently, biological systems must maintain fine control over the uptake, transport, storage, and use of iron. This research project is to investigate a ferroxidase enzyme that plays a critical role in biological metabolism. Molecular biological and genetic studies of the organism Saccharomyces cerevisiae revealed the existence of a novel eukaryotic iron uptake pathway. A cell surface ferrireductase provides ferrous ions for two different membrane transport systems. One mediates iron(II) uptake under iron-replete conditions and also transports other divalent metal ions. The other consists of an oxidase-permease complex that operates under low-iron conditions and is very selective for iron(II). This latter one, Fet3p, is a 72 kDa membrane-bound ferroxidase that belongs to a class of enzymes known as multi-copper oxidases. Fet3p is a smaller protein that appears more amenable to detailed study because of the availability of a soluble variant that lacks the membrane domain. This project will explore several kinetic and structural aspects of Fet3p in order to gain mechanistic insights into the role of multicopper ferroxidases in iron homeostasis. This research will include aspects of dioxygen reduction as well as iron oxidation and will provide fundamental insights into the function of multicopper ferroxidases and their role in iron metabolism. Techniques that will be used to accomplish this task include, stopped-flow spectroscopic studies under different conditions such as pH, equilibrium dialysis, and NMR spectroscopy.l

0000989 stahl过渡金属在细胞氧化还原反应中起重要作用。铁是生物学中含量最多的过渡金属离子，它面临着双重挑战：在生理条件下，还原态可能有毒，氧化态非常不溶。因此，生物系统必须对铁的吸收、运输、储存和使用保持良好的控制。本研究项目是研究一种在生物代谢中起关键作用的氧化铁酶。对酿酒酵母的分子生物学和遗传学研究揭示了一种新的真核铁摄取途径的存在。细胞表面铁还原酶为两种不同的膜运输系统提供铁离子。一个介导铁（II）摄取在铁充满的条件下，也运输其他二价金属离子。另一种由氧化酶-渗透酶复合物组成，该复合物在低铁条件下起作用，并且对铁（II）具有很强的选择性。后者，Fet3p，是一种72kda的膜结合铁氧化酶，属于一类被称为多铜氧化酶。Fet3p是一种更小的蛋白质，由于缺乏膜结构域的可溶性变异，它似乎更适合于详细的研究。该项目将探索Fet3p的几个动力学和结构方面，以获得多铜氧化铁酶在铁稳态中作用的机制见解。这项研究将包括双氧还原和铁氧化的方面，并将为多铜氧化铁酶的功能及其在铁代谢中的作用提供基本的见解。将用于完成这项任务的技术包括不同条件下的停流光谱研究，如pH值、平衡透析和核磁共振光谱