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: 3308854
• 负责人: ROBERT P GUNSALUS
• 金额: $ 18.21万
• 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/3308854
• 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.

该研究项目的目的是阐明机制 负责控制细胞色素O氧化酶的表达 （cyoabcde）和细胞色素d氧化酶（Cydab）基因 细菌，大肠杆菌。这两个操纵子编码两个替代方案 酶复合物可减少氧气。 他们在最佳下表达 有氧或微氧曲系条件，允许细胞产生A 通过质子生成随后的ATP的化学潜力 易位ATPase。 该潜力也用于质子驱动 溶质摄取和细胞运动。 由cyoabcde编码的酶和 Cydab基因代表了许多其他许多其他细胞色素氧化酶 包括肠细菌，各种兼性土壤在内的微生物 细菌，至少有一些强大的有氧细菌。 我们 建议研究细胞色素o（cyoabcde）和 大肠杆菌的细胞色素d（Cydab）氧化酶基因作为了解如何了解的模型 这些有氧细胞功能受到反应变化的调节 环境条件。 关于机制知之甚少 负责此控制。 我们将研究FNR ARCA的作用 和HIMA基因产品在这些过程中，以更好地了解 它们采取的机制。 控制细胞色素D氧化酶（CYDAB） 基因表达将通过局部诱变和筛选来检查 用于顺式作用调节突变。 DNA结合研究将是 进行的是为FNR和ARCA蛋白定位调节位点。 还将使用细胞色素O氧化酶（CyoAbcde）进行类似的研究 基因确定FNR和ARCA蛋白如何影响其表达。 CAP在CyABCDE表达中的作用也将进行检查。 到 了解ARCA和ARCB基因产物的水平在 细胞，将使用LACZ融合矢量系统检查它们的表达。 最后，氧浓度和生长速率对CyoAbcde的影响 Cydab基因表达将进行测试，以更好地了解 大肠杆菌细胞使用氧气的生理学。