FUNCTIONS AND PROPERTIES OF (2FE-2S) CENTERS

含有Fe 2（μ 2-S）2核的铁硫簇合物（[2Fe-2S]簇合物）是 自然界中最普遍的电子载体之一， 线粒体呼吸系统复合物I、II和III的组分 链最近的研究还表明，（2Fe-2S） 铁-硫簇组装中的簇，铁插入卟啉中， 形成血红素，由脱硫生物素合成生物素，质子 转运，调节过程中的氧化应激反应， 虽然[2Fe-2S]簇的精确作用 在这些重要的生物学过程中的作用还没有完全确定。的 这项研究的长期目标是详细了解 分子水平上的生物（2Fe-2S）的物理化学性质 特别强调决定中点的因素 潜力和它们明显的功能多样性的起源。 最终，这将有助于加深对人类起源的理解。 原卟啉症和与呼吸抑制有关的疾病 链酶 该方法涉及使用生物物理光谱技术，电子 顺磁共振，紫外/可见/近红外吸收，圆二色性 磁感应圆二色性和共振拉曼， 研究了[2Fe-2S]的电子、磁性和结构性质 中心在广泛的天然和突变的酶和蛋白质。这些 包括人和蓝细菌铁氧化还原蛋白、人铁螯合酶 菠菜二羟酸脱氢酶，大肠杆菌生物素合酶， 棕色固氮菌nifU基因产物。此外，酶和 蛋白质提取自或密切相关的复合物I，II和III的 将研究线粒体呼吸链，即个体 大肠杆菌副球菌NADH脱氢酶亚单位 延胡索酸还原酶和分离自 牛心脏线粒体。

Iron-sulfur clusters containing a Fe2(mu2-S)2 core ([2Fe-2S] clusters) are one of the most ubiquitous electron carriers in nature and are integral components of Complex I, II, and III of the mitochondrial respiratory chain. Recent studies have also implicated the involvement of (2Fe-2S] clusters in iron-sulfur cluster assembly, iron insertion into porphyrin to form hemes, the synthesis of biotin from dethiobiotin, proton translocation, regulatory processes in response to oxidative stress and dehydratase reactions, although the precise role of the [2Fe-2S] clusters in these important biological processes has yet to be fully defined. The long-term goal of this research is a detailed understanding at the molecular level of the physicochemical properties of biological (2Fe-2S] centers with particular emphasis on the factors determining midpoint potential and the origin of their apparent functional diversity. Ultimately this will lead to enhanced understanding of the origin of human protoporphyria and diseases associated with inhibition of the respiratory chain enzymes. The approach involves using biophysical spectroscopic techniques, electron paramagnetic resonance, UV/visible/near-IR absorption, circular dichroism and magnetically induced circular dichroism, and resonance Raman, to investigate the electronic, magnetic and structural properties of [2Fe-2S] centers in a wide range of native and mutated enzymes and proteins. These include human and cyanobacterial ferredoxins, human ferrochelatase, spinach dihydroxyacid dehydratase, Escherichia coil biotin synthase, the Azotobacter vinelandii nifU gene product. In addition, enzymes and proteins extracted from or closely related to Complex I, II and III of the mitochondrial respiratory chain will be investigated, i.e. individual subunits of Paracoccus denitrificans NADH dehydrogenase, Escherichia coli fumarate reductase and a soluble Rieske protein fragment isolated from bovine heart mitochondria.