MOLECULAR BASIS AND ENZYMOLOGY OF MICROBIAL BIOSYNTHESIS

正常和健康的细胞活动依赖于协调一致的 基因调控和蛋白质功能的相互作用。我们的主要利益和 长期目标是了解影响基因和生物化学因素 一条重要的代谢途径，磷酸戊糖途径的功能， 几乎所有组织的新陈代谢都需要。通过添加 有两种独特的酶，这种途径以纯粹的生物合成模式发挥作用，例如 这些组织获得了利用二氧化碳作为碳源的能力。Uner 在这些条件下，该途径的其他酶，包括转酮醇酶(TK) 和表异构体(几乎在所有生物体中都有)作为生物合成酶。 催化剂，与它们在体内的通常作用不同。这其中的结构基因 途径已经被分离，并在两个不同的操纵子中关联 球形红细菌中的不同染色体，均受控制 通过一个单一的转录激活蛋白。《规则》受以下因素的影响 其他监管机构也是如此，包括一个全球信号转导系统 还控制氮和能量代谢。因此，这项研究将寻求 了解这些监管决定因素如何影响 细胞功能所需的相互依赖的新陈代谢，涉及分子 来自不止一条染色体的信号。发出级联信号的监管事件 将建立受外部刺激影响的反应的范围。 上述研究也提供了调查详细情况的机会 最近发现的调节分子的生物化学，这样的功能 这些蛋白可能与它们的结构和调控有关 他们影响的过程。包括在THER结构-功能研究中 项目是催化重要的磷酸戊糖相互转化的酶， 它们中的每一个在新陈代谢中都起着重要的作用。例如，Tk是 所有细胞的硫胺素代谢所需及其功能变化 特性会导致严重的病理，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 每一种酶、重组系统都将被用来促进努力学习 这些蛋白质如何在生物合成中具体发挥作用，以及如何控制 它们的活动会影响正常的细胞代谢。

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.