IRON-SULFUR PROTEINS AS BOUND ELECTRON CARRIERS

铁硫蛋白作为结合电子载体

• 批准号: 3270089
• 负责人: RICHARD MALKIN
• 金额: $ 11.8万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 1977
• 资助国家: 美国
• 起止时间: 1977-07-01 至 1987-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3270089
• 关键词: Chlorophyta; Rhodopseudomonas; acidity /alkalinity; chemical structure function; chloroplasts; cytochromes; electron spin resonance spectroscopy; electron transport; genetic manipulation; hemoprotein structure; photosynthesis; quinones; sulfur compounds

Energy transduction in membranes involves proton translocation which is coupled to electron transport through bound electron carriers. One group of electron transport proteins involved in this process is the iron-sulfur proteins. An integral protein complex involved in energy transduction in mitochondrial, chromatophore and chloroplast membranes is the cytochrome b-c complex which contains an iron-sulfur protein known as the Rieske iron-sulfur center. Previous studies have shown this center interacts with quinone molecules but details of this interaction are not understood and these are critical in understanding electron transfer through this energy transducing site. Factors which are important in semiquinone stabilization remain to be defined in molecular terms. We will study the interaction of inhibitory quinone analogs which bind to the Rieske center in order to determine structure-function relationships of this interaction. This will involve EPR techniques in conjunction with redox potentiometry. The techniques of resolution and reconstitution will be used to characterize the interaction of physiologically active quinones with the Rieske center. We shall determine the organizational structure of a cytochrome complex from photosynthetic membranes which has many functional similarities to the mitochondrial complex. The possible role of quinone binding proteins and quinone free-radical species in electron transport processes of this complex will also be considered. Finally, we plan a characterization of another class of iron-sulfur proteins, NADH dehydrogenases, of simpler composition than their mitochondrial counterpart in order to assess the role of iron-sulfur centers in energy transduction associated with these enzymes. These experiments will involve both the bound and soluble enzyme and will examine EPR properties of the associated iron-sulfur center(s). These studies should provide a description in molecular terms of the function of bound iron-sulfur centers in the basic cellular process of energy transduction which results in the synthesis of ATP.

膜中的能量转导涉及质子移位， 通过束缚电子载体耦合到电子传输。 一组 参与这一过程的电子传递蛋白是铁硫蛋白， proteins. 一种参与能量转导的完整蛋白质复合物， 线粒体、色素细胞和叶绿体膜是细胞色素 b-c复合物，其中含有一种称为Rieske的铁硫蛋白 铁硫中心 以前的研究表明，该中心与 醌分子，但这种相互作用的细节尚不清楚， 这些对于理解电子通过这种能量的转移至关重要 转导位点。 半醌稳定化中的重要因素 仍然需要用分子术语来定义。 我们将研究 抑制性醌类似物，其与Rieske中心结合， 确定这种相互作用的结构-功能关系。 这将 涉及EPR技术与氧化还原电位测定法。 的 分辨率和重构技术将用于表征 生理活性醌与Rieske中心的相互作用。 我们将确定细胞色素复合物的组织结构 从光合作用膜，有许多功能上的相似性， 线粒体复合体 醌结合蛋白的可能作用， 醌自由基物种在电子传递过程中，这 也将考虑复杂。 最后，我们计划对 另一类铁硫蛋白，NADH脱氢酶， 组成比他们的线粒体对应，以评估 铁硫中心在与这些相关的能量转导中的作用 内切酶 这些实验将涉及结合酶和可溶性酶 并将检查相关的铁-硫中心的EPR性质。 这些研究应该提供一个分子方面的描述， 结合铁硫中心在细胞分裂基本过程中的作用 能量转换导致ATP的合成。