MECHANISM OF CARBOHYDRATES TRANSPORT IN BACTERIA

磷酸烯醇丙酮酸：糖磷酸转移酶系统（PTS）是一种 鼠伤寒沙门氏菌和大肠杆菌中的复合酶系统 催化伴随的跨膜转运和磷酸化 糖的底物。 它还规定了各种 不通过PTS催化的基团移位吸收的碳源 机制 我们实验室最近的研究提供了新的信息 关于临时秘书处发挥催化作用的机制， 调节糖的摄取。 具体来说，我们已经纯化了甘露醇 渗透酶（酶II-mtl）的同质性，表征和重建其 人工膜中的转运功能，克隆并测序其 结构基因，并建立了PTS控制 其他Permeases的活动。 拟议研究的目的是 扩大我们对己糖醇转运的理解， 目前的假设，并建立新的监管机制。 两 将采用生物化学和遗传学方法。 1.酶II-mtl的结构和甘露醇转运机制。 我们将 采取免疫化学家、蛋白质化学家和 分子遗传学家试图将酶II-mtl的结构与 它的功能和规则。 我们还将使用分子遗传学方法 来研究它的生物起源 2.酶II-gut-IIIgut对结构的比较研究 以及葡萄糖醇转运的机制。 葡萄糖醇特异性PTS酶 将通过生物化学和分子遗传学方法进行研究。 将强调与甘露醇系统的比较。 3. PTS对大肠杆菌甘油激酶的调控机制coli、S. 鼠伤寒沙门氏菌和B.枯草杆菌。 关于管制的研究 PTS的酶IIIg +-c的甘油激酶将在E.大肠杆菌， S.鼠伤寒沙门氏菌和B.枯草杆菌。 这些研究将扩大到 腺苷酸环化酶和各种渗透酶。 4. PTS介导的氨基酸利用调控机制 克雷布斯循环中间体。 crrB和fruR基因的参与。 遗传技术和生物化学方法将被应用于尝试 来定义一种新的调节机制的分子细节。 新 发现的PTS蛋白质可能参与调控， 表征了

The phosphoenolpyruvate: sugar phosphotransferase system (PTS) is a complex enzyme system which in Salmonella typhimurium and Escherichia coli catalyzes the concomitant transmembrane transport and phosphorylation of its sugar substrates. It also regulates the utilization of a variety of carbon sources not taken up via the PTS-catalyzed group translocation mechanism. Recent studies in our laboratory have provided new information regarding the mechanisms by which the PTS functions in catalysis and regulation of sugar uptake. Specifically, we have purified the mannitol permease (EnzymeII-mtl) to homogeneity, characterized and reconstituted its transport function in an artificial membrane, cloned and sequenced its structural gene, and established the mechanism by which the PTS controls the activities of other permeases. The purpose of the proposed research is to expand upon our understanding of hexitol transport, to further our current hypotheses and to establish novel regulatory mechanisms. Both biochemical and genetic approaches will be taken. 1. Structure of Enzyme II-mtl and mechanism of mannitol transport. We will take the approaches of the immunochemist, the protein chemist and the molecular geneticist to try to correlate structure of Enzyme II-mtl with its function and regulation. We will also use molecular genetic approaches to study its biogenesis. 2. Comparative Studies on the Structure of the Enzyme II-gut-IIIgut pair and the mechanism of glucitol transport. The glucitol-specific PTS enzymes will be studied by biochemical and molecular genetic approaches. Comparisons with the mannitol system will be emphasized. 3. Mechanism of PTS-mediated control of glycerol kinase in E. coli, S. typhimurium and B. subtilis. Studies concerned with the regulation of glycerol kinase by Enzyme IIIg+-c of the PTS will be emphasized in E. coli, S. typhimurium and B. subtilis. These studies will be extended to adenylate cyclase and various permeases. 4. Mechanism of PTS-mediated control of the utilization of amino acids and Krebs cycle intermediates. Involvement of the crrB and fruR genes. Genetic techniques and biochemical approaches will be applied in attempts to define the molecular details of a novel regulatory mechanism. Newly discovered proteins of the PTS which may be involved in regulation will be characterized.