BACTERIAL PERMEASE INVOLVED IN CHEMOTAXIS AND REGULATION

描述：拟议的研究将探索PcaK的功能，一种 最近从恶臭假单胞菌中提取的蛋白质具有新颖性 既能作为化学感受器又能作为膜结合的渗透酶。 PcaK识别的底物是芳香化合物4-羟基苯甲酸酯。 实验将探索PcaK的传输特性并识别 PcaK的结构特征和氨基酸残基 要么是趋化性，要么是运输，或者两者兼而有之。还将进行研究 确定甲基接受性趋化蛋白和一般趋化性 恶臭假单胞菌中的蛋白质，并确定这些蛋白质中的哪一种或其他蛋白质 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 一些渗透酶基因受“区域”分子支配的假说 使细菌能够降解结构上相关的控制机制 根据优选的层次结构的芳香化合物。监管要素 负责抑制4-羟基苯甲酸转运(pcaK表达) 将确定首选的碳源--苯甲酸盐。建议数 研究应拓宽目前关于细菌致病机制的概念 化学感受器和感觉传导。结果也应该会导致 芳香族化合物检测模型的开发扩展到 不同的细菌，可能对这种大型和 一组实际意义重大的化合物，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.