GENETIC CONTROL OF NITRATE RESPIRATION IN E COLI

大肠杆菌硝酸盐呼吸的基因控制

• 批准号: 3291473
• 负责人: Valley J. Stewart
• 金额: $ 11.62万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-07-01 至 1994-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3291473
• 关键词: DNA binding protein; Enterobacteriaceae; Escherichia coli; anaerobic bacteria; bacterial genetics; cell free system; fusion gene; gel electrophoresis; gene expression; genetic manipulation; genetic regulation; microorganism metabolism; mutant; nitrate reductases; nitrates; operon; regulatory gene; respiratory enzyme; structural genes

Enterobacteria efficiently regulate their respiratory metabolism in response to availability of alternate electron acceptors such as oxygen, nitrate and fumarate. This regulation is coordinated to ensure use of the most efficient respiratory pathway. In the absence of oxygen, nitrate, the preferred anaerobic electron acceptor, induces synthesis of enzymes for nitrate respiration (formate dehydrogenase-N and nitrate reductase) while repressing the synthesis of other anaerobic respiratory enzymes such as fumarate reductase. The long-term goals of this project are to understand the physiological and genetic mechanisms by which nitrate coordinately regulates the synthesis of different anaerobic pathways in different ways. Previous work has identified two genes, narL and narX, which are required for nitrate induction of nitrate reductase synthesis and nitrate repression of fumarate reductase synthesis. The narL gene product, NARL, is hypothesized to be a DNA-binding protein that regulates transcription in response to nitrate. The narX gene product, NARX, is hypothesized to convert NARL to its repressor form. NARL and NARX show sequence similarity to the group of "two-component regulatory systems" involved in signal transduction. This project will define the roles of narL and narX in regulation by isolating and characterizing altered function mutations in these genes, by expressing narL and narX independently of each other under various growth conditions, and by analyzing binding of NARL to its target DNA sites. The structure and expression of the narL complex operon will be analyzed by operon and gene fusions and by transcript mapping, in order to understand the regulation of narX and narL expression. A search will be made for a hypothetical gene, "narQ", that may be required for conversion of NARL to its activator form. Finally, the structural genes for formate dehydrogenase-N will be identified, and their regulation by nitrate and NARL will be analyzed by genetic and molecular biological methods. Together, these studies will provide a more detailed view of how nitrate regulates and coordinates anaerobic metabolism.

肠杆菌有效调节其呼吸新陈代谢 对替代电子受体（例如氧气）的可用性的响应， 硝酸盐和富马酸盐。 该法规是协调的，以确保使用 最有效的呼吸道途径。 在没有氧气的情况下，硝酸盐， 首选的厌氧电子受体，诱导酶的合成 硝酸盐呼吸（甲酸脱氢酶-N和硝酸盐还原酶），而硝酸盐呼吸 抑制其他厌氧呼吸酶的合成，例如 富马酸盐还原酶。 该项目的长期目标是了解 硝酸盐协同的生理和遗传机制 以不同的方式调节不同厌氧途径的合成。 先前的工作已经确定了两个基因Narl和Narx，这是必需的 用于硝酸盐还原酶合成和硝酸盐抑制作用。 富马酸还原酶合成。 NARL基因产品Narl是 假设是一种调节转录的DNA结合蛋白 对硝酸盐的反应。 Narx基因产品Narx被认为是 将NARL转换为其阻遏物形式。 NARL和NARX显示序列相似性 信号涉及的“两个组件调节系统”组 转导。 该项目将通过 通过隔离和表征这些基因中功能突变的改变 在各种增长下彼此独立地表达Narl和Narx 条件，并通过分析NARL与其靶DNA位点的结合。 这 NARL复合操纵子的结构和表达将通过 操纵子和基因融合以及成绩单映射，以便理解 NARX和NARL表达的调节。 将进行搜索 假设基因“ narq”，这可能是将narl转化为 其激活器形式。 最后，甲酸的结构基因 将确定脱氢酶-N，并通过硝酸盐调节 NARL将通过遗传和分子生​​物学方法分析。 这些研究将共同​​提供硝酸盐的更详细观点 调节并协调厌氧代谢。