MOLECULAR BASIS AND ENZYMOLOGY OF MICROBIAL BIOSYNTHESIS

微生物生物合成的分子基础和酶学

• 批准号: 6386037
• 负责人: F ROBERT TABITA
• 金额: $ 29.99万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-05-01 至 2004-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6386037
• 关键词: Rhodospirillales; affinity labeling; bacterial genetics; enzyme mechanism; enzyme substrate; fructose biphosphatase; gene deletion mutation; gene expression; genetic promoter element; genetic regulation; genetic regulatory element; genetic transcription; microorganism metabolism; nucleic acid sequence; pentose phosphate shunt; phosphorylase kinase; protein structure function; recombinant DNA; recombinant proteins; site directed mutagenesis; structural genes; transaldolase /transketolase; transcription factor

Normal and healthy cellular activity is dependent on a concerted interplay of genetic regulation and protein function. Our primary interest and longterm goal is to understand genetic and biochemical factors which influence the function of an important metabolic route, the pentose phosphate pathway, required for the metabolism of virtually all organizms. With the addition of two unique enzymes, this pathway functions in a purely biosynthetic mode, such that organizms gain the capacity to use carbon dioxide as a carbon source. Uner these conditions, other enzymes of the pathway, including transketolase (TK) and epimerase (found in virtually all organism) function as biosynthetic catalysts, differen from their usual role in vivo. Structural genes of this pathway have been isolated and are associated in distinct operons on two different chromosomes in the bacterium Rhodobacter sphaeroides, all controlled by a single transcriptional activator protein. The "regulon" is influenced by other regulators as well, including a global signal transduction system that also controls nitrogen and energy metabolism. This study will thus seek to understand how such regulatory determinants influence the totality of interdependent metabolism required for cellular function, involving molecular signals from more than one chromosome. Regulatory events that signal a cascade of responses influenced by external stimuli will be established. The above studies also present opportunities to investigate the detailed biochemistry of regulator molecules recently discovered, such tha th function of these proteins may be related to their structure, and to the regulatory processes they influence. Included in the structure-function studies of thie project are enzymes that catalyze important pentose phosphate interconversions, each of which plays a significant role during metabolism. For example, TK is required fro thiamine metabolism in all cells and alteration of its functional properties leads to severe pathologies including nutritional deficiency, alcoholism, Wernicke-Korsakoff encephalopathy, and Alzheimer's disease. For each enzyme, recombinant systems will be used to facilitate efforts to learn how these proteins function specifically in biosynthesis and how control of their activity influences normal cellular metabolism.

正常和健康的细胞活动依赖于协调一致的 遗传调节和蛋白质功能的相互作用。我们的主要利益和 长期的目标是了解遗传和生物化学因素， 一个重要的代谢途径的功能，戊糖磷酸途径， 几乎所有有机体的新陈代谢都需要这种物质。通过添加 两种独特的酶，这种途径以纯粹的生物合成模式发挥作用， 组织获得了利用二氧化碳作为碳源的能力。乌纳 这些条件下，其他酶的途径，包括转酮酶（TK） 和差向异构酶（在几乎所有生物体中发现）的功能是生物合成 催化剂，使其在体内发挥通常的作用。结构基因 途径已被分离，并在两个不同的操纵子相关 不同的染色体在细菌Rhodobacter sphaeroides，所有控制 一个转录激活蛋白。“调节子”受 还有其他调节因子，包括一个全局信号转导系统， 还控制氮和能量代谢。因此，本研究将力求 了解这些监管决定因素如何影响整体 细胞功能所需的相互依赖的代谢，涉及分子 来自不止一个染色体的信号。信号级联的监管事件 受外部刺激影响的反应将被建立。 上述研究也提供了机会，以调查详细的 最近发现的调节分子的生物化学， 这些蛋白质的组成可能与其结构以及调节作用有关 他们影响的过程。包括在结构-功能研究中， 项目是催化重要的戊糖磷酸相互转化的酶， 每一种都在新陈代谢过程中起重要作用。例如，TK 硫胺素代谢所需的所有细胞和改变其功能 这些特性导致严重的病理，包括营养缺乏， 酒精中毒、韦尼克-科萨科夫脑病和阿尔茨海默病。为 每种酶，重组系统将用于促进学习的努力 这些蛋白质在生物合成中的特殊功能， 它们的活性影响正常的细胞代谢。