REGULATION OF E COLI CYTOCHROME OXIDASE AND TCA CYCLE

大肠杆菌细胞色素氧化酶和 TCA 循环的调节

• 批准号: 2838606
• 负责人: ROBERT P GUNSALUS
• 金额: $ 22.42万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-09-01 至 2001-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2838606
• 关键词: DNA footprinting; Escherichia coli; Krebs' cycle; aerobic bacteria; bacterial genetics; bacterial proteins; cytochrome oxidase; gene expression; microorganism metabolism; oxygen consumption; respiratory enzyme; site directed mutagenesis; transcription factor

DESCRIPTION: A variety of cellular pathways for carbon and electron flow in the bacterium Escherichia coli and in other enteric bacteria are differentially employed depending on whether molecular oxygen is present in the cell environment. These include two distinct pathways for electron flow to oxygen via the cytochrome o and d oxidases encoded by the cyoABCDE and cydAB operons, respectively, or electron flow to any of a number of anaerobic electron acceptors. The alternative pathways for carbon flow include use of the TCA cycle reactions in a cyclic pathway during aerobic conditions, use of the branched and non-cyclic TCA pathway during aerobic and/or anaerobic conditions, and the mixed acid fermentation pathway used when no electron acceptors are present. This proposal addresses how the cell accomplishes the aerobic/anaerobic regulation of genes for the two cytochrome oxidase enzymes, and the genes of the TCA cycle pathway. The cell has two distinct regulators, comprised of the Fnr and the ArcA/ArcB proteins that participate in this task. Together, they coordinate gene transcription to help adjust carbon flow with electron flow in the cell for balanced and optimal growth. However, little is known about how the regulation of gene expression occurs at the molecular level. The major aims of this proposal are to understand how the ArcA and Fnr proteins participate in regulating cyoABCDE, cydAB, sdhCDAB, and icd gene expression. The binding sites of the proteins to DNA will be examined to understand how they function in repression or activation of transcription. The mechanism for microaerobic gene control of the cydAB genes will be studied, as will the coordinate regulation of the TCA cycle genes. Finally, the autoregulation of the arcA gene will be further examined since the ArcA protein is a major participant in the aerobic anaerobic switch in E. coli. These studies should provide a detailed understanding of how the cell coordinates pathways for electron and carbon flow within the cell during transition between oxygen rich and oxygen limiting conditions.

描述：多种碳和电子流的细胞途径 细菌大肠杆菌和其他肠细菌是 取决于分子氧是否存在于 细胞环境。 这些包括两个不同的电子流途径 通过cyoabcde编码的细胞色素O和D氧化酶到氧气到氧气 Cydab操纵子分别或电子流到许多中的任何一个 厌氧电子受体。 碳流的替代途径 包括在有氧运动过程中使用TCA循环反应 有氧运动期间的条件，使用分支和非环状TCA途径 和/或厌氧条件，以及使用的混合酸发酵途径 当不存在电子受体时。 该提议解决了如何 细胞完成两者的基因的有氧/厌氧调节 细胞色素氧化酶和TCA循环途径的基因。 这 细胞具有两个不同的调节剂，由FNR和ARCA/ARCB组成 参与此任务的蛋白质。 它们在一起坐标基因 转录以帮助通过电池中的电子流来调节碳流 平衡和最佳增长。 但是，关于如何 基因表达的调节发生在分子水平。 主要目的 该建议的内容是了解ARCA和FNR蛋白如何参与 在调节cyoabcde，cydab，sdhcdab和ICD基因表达中。 这 将检查蛋白质与DNA的结合位点，以了解它们如何 在抑制或激活转录中的功能。 机制 将研究Cydab基因的微氧化基因对照，也将研究 TCA循环基因的坐标调节。 最后，自动调节 由于ARCA蛋白是主要的 大肠杆菌中有氧厌氧开关的参与者。 这些研究 应提供对细胞如何坐标途径的详细理解 对于电池内的电子和碳流过渡期间 富氧和氧气限制条件。