BACTERIAL PERMEASE INVOLVED IN CHEMOTAXIS AND REGULATION

描述：拟议的研究将探索PcaK的功能， 最近描述的来自恶臭假单胞菌的蛋白质具有新的 同时作为化学感受器和膜结合通透酶的能力。 PcaK识别的底物是芳香族化合物4-羟基苯甲酸酯。 实验将探索PcaK的输运性质，并确定 PcaK的结构特征和氨基酸残基是必不可少的 或者趋化性或者运输，或者两者都有。 还将开展研究， 定义甲基接受趋化性蛋白和一般趋化性 恶臭假单胞菌中的蛋白质，并确定这些或其他蛋白质中 与PcaK相互作用，启动感觉信息的传输， 细菌鞭毛马达 PcaK还将用于测试 一些通透酶基因受“区域性”分子调控假说 控制机制，使细菌降解结构相关的 芳族化合物根据优选的等级。 调控元件 负责抑制4-羟基苯甲酸转运（pcaK表达） 苯甲酸盐，优选的碳源。 拟议 研究应拓宽当前有关细菌作用机制的概念 化学感受和感觉传导。 结果还应导致 芳香族化合物检测模型的开发，该模型扩展到 不同的细菌，可能是这个大的， 实际上是一组重要的化合物，其中许多是致癌物质。

DESCRIPTION: The proposed research will explore the function of PcaK, a recently described protein from Pseudomonas putida that has the novel ability to function as both a chemoreceptor and a membrane-bound permease. The substrate recognized by PcaK is the aromatic compound 4-hydroxybenzoate. Experiments will explore the transport properties of PcaK and identify structural features and amino acid residues of PcaK that are essential for either chemotaxis or transport, or both. Studies will also be carried out to define methyl-accepting chemotaxis proteins and general chemotaxis proteins in P. putida and to determine which of these or other proteins interacts with PcaK to initiate the transmission of sensory information to the bacterial flagellar motors. PcaK will also be used to test the hypothesis that some permease genes are subject to "regional" molecular control mechanisms that enable bacteria to degrade structurally related aromatic compounds according to a preferred hierarchy. Regulatory elements responsible for repression of 4-hydroxybenzoate transport (pcaK expression) by benzoate, a preferred carbon source, will be identified. The proposed studies should broaden current concepts about mechanisms of bacterial chemoreception and sensory transduction. The results should also lead to the development of a model of aromatic compound detection that extends to diverse bacteria and possibly to diverse members of this large and practically significant group of compounds, many of which are carcinogens.