ATP-DEPENDENT PROTEIN KINASES IN STREPTOCOCCI

在革兰氏阳性细菌如链球菌属中， 葡萄球菌，芽孢杆菌和乳酸杆菌， 磷酸烯醇丙酮酸：糖磷酸转移酶系统 运输和磷酸化各种糖，包括 葡萄糖、果糖、甘露醇、乳糖和蔗糖。 广泛 有证据表明，在所有这些细菌中， 吸收和流出由ATP依赖性蛋白控制 磷酸化 一种磷酸化丝氨酰的HPr激酶 HPr中的残基和HPr（Ser）P磷酸酶已被 在体外表征并参与调节。 为了进一步表征这种新的细菌调节剂， 我们提出的机制，采取联合生化遗传 approach. 具体而言，我们计划： 1. 利用新开发的交换试验，以确定 HPr（丝氨酰）磷酸化对 HPr与PTS的所有相关蛋白质。 2. 分离并表征PTS缺陷突变体 调节系统，以确定生理功能 the system. 3. 克隆编码HPr（ser）激酶的基因， 磷酸酶，以允许一级结构确定 这些蛋白质，并促进随后的分子遗传 分析. 4. 进一步研究糖流出的机制，通过 PTS的酶II。 5. 确定HPr（ser）的生理功能 在异型发酵乳酸菌中的磷酸化， 据报道缺少完整的PTS。 6. 定义酶III 1ac 金黄色葡萄球菌调节乳糖操纵子表达。

In Gram-positive bacteria such as species of Streptococcus, Staphylococcus, Bacillus and Lactobacillus, the phosphoenolpyruvate: sugar phosphotransferase system (PTS) transports and phosphorylates a variety of sugars including glucose, fructose, mannitol, lactose and sucrose. Extensive evidence suggests that in all of these bacteria the rates of sugar uptake and efflux are controlled by ATP-dependent protein phosphorylation. An HPr-kinase which phosphorylates a seryl residue in HPr, and an HPr(Ser)P phosphatase have been characterized in vitro and implicated in regulation. In order to further characterize this novel bacterial regulatory mechanism we propose to take a combined biochemical genetic approach. Specifically we plan to: 1. Utilize a newly developed exchange assay in order to define the effect of HPr(seryl) phosphorylation on the interactions of HPr with all of the relevant proteins of the PTS. 2. Isolate and characterize mutants defective in the PTS regulatory system in order to define the physiological functions of the system. 3. Clone the genes which encode the HPr(ser) kinase and phosphatase in order to allow primary structural determination of these proteins and to facilitate subsequent molecular genetic analysis. 4. Further examine the mechanisms of sugar efflux via the Enzymes II of the PTS. 5. Determine the physiological function of HPr(ser) phosphorylation in heterofermentative lactic acid bacteria which have been reported to lack an intact PTS. 6. Define the mechanism by which Enzyme III 1ac of Staphylococcus aureus regulates lac operon expression.