EFFECTS OF FATTY ACIDS ON STRUCTURE, REACTIVITY, AND FUNCTION OF CYTOCHROME C

脂肪酸对细胞色素 C 的结构、反应性和功能的影响

• 批准号: 6271598
• 负责人: MICHAEL D JOHNSON
• 金额: $ 4.35万
• 依托单位: NEW MEXICO STATE UNIVERSITY LAS CRUCES
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-01 至 1999-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6271598
• 关键词: chemical binding; cytochrome c; electrodes; electron transport; enzyme activity; enzyme structure; fatty acids; high performance liquid chromatography; nuclear magnetic resonance spectroscopy; protein structure function; spectrometry

Fatty acids ar a class of poorly soluble, hydrophobic metabolites that are used as building blocks for complex membrane lipids, energy storage and energy production. Under normal circumstances, the total concentration of fatty acids in the cell are kept within strict limits. During certain pathological conditions (ischemia/reperfusion, diabetes) total fatty acid concentrations can increase dramatically (80%) in some experiments). It is thought that such concentrations of fatty acids will outstrip the capacity of the cell to remove them from the cytoplasm. The effects of these elevated fatty acids levels however is not well understood. Preliminary experiments in this laboratory have demonstrated that cytochromes c are affected by the presence of fatty acids at physiological levels. The UV-VIS spectrum of the protein changes dramatically upon binding. It was originally thought that this must involve specific rearrangement of the protein structure around the heme ring. Subsequent 1/H-NMR experiments have demonstrated that the methionine sulfur atom (bonded directly the iron) is shifted away from the heme ring upon the binding of fatty acids. Cyclic voltammetric experiments have shown that the redox potential of cytochrome c is shifted when fatty acids bind to the protein. These observations indicate that fatty acids may have an important role in controlling the electron transport function of cytochrome c. Structural implications also suggest that cytochromes may be an important component fatty acid metabolism as well. Specific research aims, based on this hypothesis, are to rigorously investigate the affects of fatty acids on the structure, function, and reactivity of cytochromes c. The interactions of cytochromes c from mammalian, plant, and microbial sources with fatty acids of varied structural features will be studied. Most studies will be with native cytochromes buy site-specific variants, supplied by other researchers, will also be investigated in order to provide a more detailed of the binding process through structural modifications of the proposed site. A variety of instrumental techniques will be used to this hypothesis. These include stopped-flow and temperature jump kinetic spectrophotometers, a rapid-scanning spectrophotometer, 1/H and 19/F NMR spectrometers (250MHz and 400MHz), HPLC, conventional diode array spectrophotometers, cyclic voltammetry, and oxygen sensitive electrodes.

脂肪酸ar an serf colledble，疏水代谢产物 用作复杂膜脂质，储能和 能源生产。 在正常情况下，总浓度为 细胞中的脂肪酸保持在严格的限制范围内。 在某些过程中 病理状况（缺血/再灌注，糖尿病）总脂肪酸 在某些实验中，浓度可以急剧增加（80％）。 它 认为这种浓度的脂肪酸将超过 细胞从细胞质中清除它们的能力。 效果 但是，这些升高的脂肪酸水平尚不清楚。 该实验室的初步实验表明 细胞色素C受到生理上脂肪酸的影响 水平。 蛋白质的UV-VIS光谱在 结合。 最初认为这必须涉及特定 血红素环周围蛋白质结构的重排。 随后的 1/H-NMR实验证明了蛋氨酸硫原子 （直接粘合铁）从血红素环上移开 脂肪酸的结合。 循环伏安实验表明 当脂肪酸与 蛋白质。 这些观察结果表明脂肪酸可能具有 控制电子传输功能的重要作用 细胞色素c。 结构的影响还表明，细胞色素可能 也是重要的成分脂肪酸代谢。 具体的 基于这一假设的研究目的是严格研究 脂肪酸对结构，功能和反应性的影响 细胞色素c。 来自哺乳动物，植物和微生物的细胞色素C的相互作用 将研究具有各种结构特征的脂肪酸的来源。 大多数研究都是针对天然细胞色素购买特定地点变体的研究， 其他研究人员提供的也将进行调查 通过结构性提供更详细的结合过程 拟议站点的修改。 该假设将使用多种仪器技术。 这些包括停止流和温度跳跃动力学 分光光度计，迅速扫描的分光光度计，1/H和19/F NMR 光谱仪（250MHz和400MHz），HPLC，常规二极管阵列 分光光度计，环状伏安法和氧敏感电极。