BIOSYNTHESIS AND REGULATION OF AROMATICS IN PSEUDOMONAS

假单胞菌中芳香族化合物的生物合成和调控

• 批准号: 3237598
• 负责人: ROY A. JENSEN
• 金额: $ 9.11万
• 依托单位: UNIVERSITY OF FLORIDA
• 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 1988-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3237598
• 关键词: Bacillus subtilis; Escherichia coli; Neurospora; Pseudomonas aeruginosa; affinity chromatography; allosteric site; aminoacid metabolism; bacterial genetics; cyclic aminoacid; density gradient ultracentrifugation; enzyme feedback; enzyme induction /repression; enzyme structure; fungal genetics; gel electrophoresis; gel filtration chromatography; genetic mapping; genetic recombination; ion exchange chromatography; microorganism genetics; microorganism metabolism; molecular biology; mutant; phenylalanine; radiotracer; thin layer chromatography; tyrosine

Pseudomonas aeruginosa is an outstanding example of a microbial pathogen which resists antimetabolite therapy. It is likewise uncommonly resistant to analog mimicks of L-tyrosine and L-phenylalanine which are effective false feedback inhibitors in vitro. This resistance is related to the existence of two simultaneously present pathway branchlets to L-phenylalanine in addition to dual branchlets to L-tyrosine. Bacillus subtilis and Euglena gracilis exemplify organisms having completely different post-prephenate pathway sequences, both of which co-exist in P. aeruginosa. Consequently, tightly blocked phenylalanine and tyrosine auxotrophs are not isolated from P. aeruginosa. Growth on fructose as carbon source invokes a limitation of early-pathway flow, presumably by depletion of PEP. This has provided a condition that facilitates the selection of regulatory mutants. A workable strategy for the sequential isolation of structural-gene mutants has also been devised. We propose to obtain mutants deficient in each structural gene of the total aromatic pathway. Deregulated mutants corresponding to enzymes subject to regulation in wild type will be isolated. In many cases sequential mutagenesis will result in strains bearing multiple mutations. The subtle effects of individual mutations will be studied by segregating individual mutations into different strains following genetic recombination. A comparison of physiological and nutritional effects caused by all possible combinations of structural-gene and regulatory mutations will be used to formulate an interpretation of the metabolic significance of the enzymological complexity that characterizes aromatic biosynthesis in P. aeruginosa. An overview of pathway-flow characteristics, pathway arrangement and regulation, and basis of resistance/sensitivity to aromatic antimetabolites will be pursued. We will locate the chromosomal map positions of each structural gene and regulatory gene available for aromatic amino acid biosynthesis as well as for pyocyanine biosynthesis and aromatic amino acid catabolism.

铜绿假单胞菌是微生物病原体的杰出例子 抵抗抗代谢物治疗。 它同样罕见 对L-酪氨酸和L-苯基丙氨酸的模拟模仿，这是有效的 体外反馈抑制剂。 这种阻力与 存在两个同时存在的途径分支到 除l-酪氨酸的双分支外，L-苯基丙氨酸。 芽孢杆菌 枯草和尤格纳·格拉西利（Euglena gracilis）典范具有完全的生物 不同的后苯二酚途径序列，这两者都在P中共存。 铜绿。 因此，紧密封闭的苯丙氨酸和酪氨酸 可营养不良不是从铜绿假单胞菌中分离出来的。 果糖的生长 碳源调用了早期流道流的限制，大概是 PEP的耗尽。 这提供了一种促进的条件 选择调节突变体。 顺序可行的策略 还设计了结构基因突变体的分离。 我们建议 获得总芳族的每个结构基因缺陷的突变体 路径。 放松管制的突变体，对应于酶 野生类型的调节将被隔离。 在许多情况下，顺序 诱变将导致菌株带有多个突变。 微妙 将通过分离个体来研究个体突变的效果 基因重组后突变成不同菌株。 一个 所有可能的生理和营养作用的比较 结构基因和调节突变的组合将用于 制定对代谢意义的解释 酶学复杂性表征了P。 铜绿。 通路流特征，途径的概述 排列和调节，以及对芳族的抗性/敏感性的基础 将追求反代谢物。 我们将找到染色体图 每个结构基因和调节基因的位置可用于 芳香氨基酸生物合成以及上酰氨酸生物合成和 芳香氨基酸分解代谢。