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: 2471310
• 负责人: ROBERT P GUNSALUS
• 金额: $ 22.95万
• 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/2471310
• 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：碳和电子流动的多种细胞途径 大肠杆菌和其他肠道细菌是 根据分子氧是否存在而有差别地使用 细胞环境。 其中包括两种不同的电子流路径 通过 cyoABCDE 编码的细胞色素 o 和 d 氧化酶转化为氧气 cydAB 操纵子分别或电子流向任意多个 厌氧电子受体。 碳流动的替代途径 包括在有氧运动期间在循环途径中使用 TCA 循环反应 有氧运动期间支链和非环状 TCA 途径的使用 和/或厌氧条件，以及所使用的混合酸发酵途径 当不存在电子受体时。 该提案解决了如何 细胞完成有氧/无氧两种基因的调节 细胞色素氧化酶和 TCA 循环途径的基因。 这 细胞有两个不同的调节因子，由 Fnr 和 ArcA/ArcB 组成 参与这项任务的蛋白质。 它们一起协调基因 转录有助于调节细胞中的碳流和电子流 均衡、最佳的增长。 然而，人们对如何 基因表达的调控发生在分子水平。 主要目标 该提案的目的是了解 ArcA 和 Fnr 蛋白如何参与 调节 cyoABCDE、cydAB、sdhCDAB 和 icd 基因表达。 这 将检查蛋白质与 DNA 的结合位点，以了解它们如何 抑制或激活转录的功能。 其机制为 将研究 cydAB 基因的微氧基因控制，以及 TCA循环基因的协调调节。 最后，自动调节 由于 ArcA 蛋白是主要的 大肠杆菌有氧厌氧转换的参与者。 这些研究 应该提供对细胞如何协调途径的详细了解 用于细胞内电子和碳在过渡期间的流动 富氧和限氧条件。