REGULATION OF HISTIDINE UTILIZATION IN STREPTOMYCES

链霉菌中组氨酸利用的调控

• 批准号: 3298462
• 负责人: KATHLEEN E KENDRICK
• 金额: $ 11.09万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-04-01 至 1994-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3298462
• 关键词: Streptomyces; bacterial genetics; enzyme induction /repression; enzyme mechanism; gene expression; histidine; microorganism growth; microorganism metabolism; molecular cloning; nitrogen metabolism; protein biosynthesis; structural genes

The utilization of the amino acid L-histidine by streptomycetes is controlled at the levels of gene expression and enzymatic activity. Histidine ammonia-lyase (histidase), the enzyme that catalyzes the first step in the conversion of histidine to glutamate, is regulated post- translationally in Streptomyces griseus by the concerted action of at least three proteins. One of these proteins can be replaced in vitro by a phosphatase, and another can be replaced by a phosphodiesterase. The proposed experiments have been designed to identify and characterize the genes and gene products involved in the control of histidase activity in S. griseus. The analysis of mutants that cannot activate histidase will facilitate the elucidation of the mechanism by which histidase is activated in vivo. The inactive and active forms of histidase will be identified by a combination of electrophoretic and immunological techniques. To determine whether histidase activity is regulated in response to changes in the streptomycete life cycle, fluctuatuations in the relative amounts of these forms during differentiation will be measured. Activation factor, the protein that converts histidase to the catalytically active form, will be purified, its activity characterized, and its structural gene cloned. The histidase structural gene will also be cloned, to facilitate analysis of the regulation of histidase activity and to permit the identification of molecular features of histidase gene expression. By these studies, we will gain a more detailed understanding of molecules involved in the regulation of nitrogen metabolism in streptomycetes. This research may also have ramifications extending to a regulatory processes functional during cellular differentiation and secondary metabolism.

链霉菌对氨基酸L组氨酸的利用 控制在基因表达和酶活性的水平上。 组氨酸解氨酶(组氨酸酶)，催化第一个 在组氨酸转化为谷氨酸的过程中，这一步骤受到后调控。 在灰色链霉菌中通过至少 三种蛋白质。这些蛋白质中的一种可以在体外被一种 另一种可以用磷酸二酯酶代替。这个 拟议中的实验旨在识别和表征 与组氨酸酶活性调控有关的基因和基因产物 灰霉菌(S.griseus)对不能激活组氨酸酶的突变体的分析将 有助于阐明组氨酸酶被激活的机制 在活体内。非活性和活性形式的组氨酸酶将由 电泳法和免疫学技术的结合。至 确定组氨酸酶活性是否受调节以响应 链霉菌的生活史，相对数量的波动 将对分化过程中的这些形式进行测量。激活因子， 将组氨酸酶转化为催化活性形式的蛋白质将 对其进行纯化、活性鉴定和结构基因克隆。 为了便于分析，还将克隆组氨酸酶结构基因 组氨酸酶活性的调节，并允许鉴定 组氨酸酶基因表达的分子特征。通过这些研究，我们将 对参与调控的分子有更详细的了解 链霉菌的氮代谢。这项研究也可能有 分叉延伸到监管流程在 细胞分化和次生代谢。