MECHANISM OF CARBOHYDRATES TRANSPORT IN BACTERIA

磷酸烯醇式丙酮酸：蔗糖磷酸转移酶系统(PTS)是一种 鼠伤寒沙门氏菌和大肠杆菌复合酶系的研究 催化伴随的跨膜转运和磷酸化 它的糖底物。它还规定了各种不同的 不是通过PTS催化的基团转位来吸收的碳源 机制。我们实验室最近的研究提供了新的信息 关于PTS在催化和免疫反应中的作用机制 糖吸收的调节。具体来说，我们提纯了甘露醇 通透酶(EnzymeII-MTL)的同质性，鉴定和重组ITS 人造膜转运功能的克隆和序列分析 结构基因，并建立了PTS控制的机制 其他许可证的活动。拟议研究的目的是 为了扩大我们对己醇转运的理解，进一步 目前的假设，并建立新的监管机制。两者都有 将采取生化和遗传方法。 1.酶II-MTL的结构及甘露醇转运机制我们会 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 它的功能和调控。我们还将使用分子遗传学方法 来研究它的生物发生。 2.酶II-GUT-IIIgut对结构的比较研究 以及葡萄糖醇的转运机制。葡糖醇特异的PTS酶 将通过生化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介导的大肠杆菌甘油激酶调控机制。 鼠伤寒杆菌和枯草芽孢杆菌。与监管有关的研究 在大肠杆菌中将强调PTS的IIIg+-c酶的甘油激酶， 鼠伤寒沙门氏菌和枯草芽孢杆菌。这些研究将扩展到 腺苷环化酶和各种通透性。 4.PTS介导的氨基酸利用调控机制和 克雷布斯循环中间体。CrrB和FruR基因的参与。 基因技术和生化方法将在尝试中应用 以确定一种新的调控机制的分子细节。新开 已发现的可能参与调节的PTS蛋白将是 特色化的。

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.