REGULATION OF THE E COLI CYTOCHROME OXIDASE GENES

大肠杆菌细胞色素氧化酶基因的调控

• 批准号: 2187223
• 负责人: ROBERT P GUNSALUS
• 金额: $ 18.64万
• 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 1997-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2187223
• 关键词: DNA footprinting; Escherichia coli; aerobic bacteria; cytochrome oxidase; enteric bacteria; enzyme complex; gene deletion mutation; gene expression; genetic promoter element; genetic regulatory element; genetic transcription; microorganism growth; mutant; nucleic acid sequence; operon; oxygen consumption; respiratory enzyme; site directed mutagenesis

The goal of this research project is to elucidate the mechanisms responsible for controlling expression of the cytochrome o oxidase (cyoABCDE) and cytochrome d oxidase (cydAB) genes in the enteric bacterium, Escherichia coli. These two operons encode the two alternative enzyme complexes for oxygen reduction. They are expressed optimally under aerobic or micro-aerobic conditions and allow the cell to generate a chemiosmotic potential for subsequent ATP generation via the proton translocating ATPase. This potential is also used for proton driven solute uptake and for cell motility. The enzymes encoded by cyoABCDE and cydAB genes are representative of the cytochrome oxidases in many other microorganisms including the enteric bacteria, various facultative soil bacteria and for at least some of the obligate aerobic bacteria. We propose to study the regulation of the cytochrome o (cyoABCDE) and cytochrome d (cydAB) oxidase genes of E. coli as a model to understand how these aerobic cell functions are regulated in response change in environmental conditions. Little is yet known about the mechanisms responsible for this control. We will study the role of the fnr, arcA, and himA gene products in these processes to better understand the mechanisms by which they act. Control of cytochrome d oxidase (cydAB) gene expression will be examined by localized mutagenesis and screening for cis-acting regulatory mutations. DNA binding studies will be performed to locate regulatory sites for the Fnr and ArcA proteins. Similar studies will also be done with the cytochrome o oxidase (cyoABCDE) genes to determine how the Fnr and ArcA proteins affect their expression. The role of CAP in cyoABCDE expression will also be examined. To understand how the levels of the arcA and arcB gene products vary in the cell, their expression will be examined using lacZ fusion vector systems. Finally, the effect of oxygen concentration and growth rate on cyoABCDE and cydAB gene expression will be tested to better understand the physiology of oxygen use by E. coli cells.

该研究项目的目标是阐明其机制 负责控制细胞色素 O 氧化酶的表达 (cyoABCDE) 和肠道中的细胞色素 d 氧化酶 (cydAB) 基因 细菌，大肠杆菌。这两个操纵子编码两种选择 用于氧还原的酶复合物。 它们在以下条件下得到最佳表达 有氧或微需氧条件并允许细胞产生 随后通过质子产生 ATP 的化学渗透势 ATP 酶易位。 该电势也可用于质子驱动 溶质吸收和细胞运动。 cyoABCDE 编码的酶和 cydAB 基因代表许多其他细胞色素氧化酶 微生物，包括肠道细菌、各种兼性土壤 细菌和至少一些专性需氧细菌。 我们 提议研究细胞色素o（cyoABCDE）的调节和 以大肠杆菌的细胞色素 d (cydAB) 氧化酶基因作为模型来了解如何 这些需氧细胞功能受到响应变化的调节 环境条件。 目前对其机制知之甚少 负责此控制。 我们将研究fnr、arcA、 和这些过程中的 HimA 基因产物，以更好地了解 他们采取行动的机制。 细胞色素 d 氧化酶 (cydAB) 的控制 将通过局部诱变和筛选来检查基因表达 用于顺式作用调节突变。 DNA 结合研究将 进行定位 Fnr 和 ArcA 蛋白的调控位点。 类似的研究也将针对细胞色素 O 氧化酶 (cyoABCDE) 进行 基因来确定 Fnr 和 ArcA 蛋白如何影响其表达。 CAP 在 cyoABCDE 表达中的作用也将被检查。 到 了解 arcA 和 arcB 基因产物的水平在 细胞，将使用 lacZ 融合载体系统检查它们的表达。 最后，氧气浓度和生长速率对cyoABCDE的影响 并将测试 cydAB 基因表达，以更好地了解 大肠杆菌细胞利用氧气的生理学。