BINDING PROTEINS FOR ACTIVE TRANSPORT AND CHEMOTAXIS

这个应用程序的长期目标是研究结构和 几种周质结合蛋白或受体蛋白的功能。这些 蛋白质是渗透性休克敏感活性的重要成分 细菌的运输和趋化作用。将使用X射线结晶学 主要是为了实现这个目标。这一目标是迫在眉睫的，因为我们 已经获得了五种受体蛋白的单晶，这些蛋白专用于 阿拉伯糖、D-半乳糖、麦芽糖、亮氨酸/异亮氨酸/缬氨酸 硫酸盐结合蛋白。此外，还研究了其晶体结构。 阿拉伯糖结合蛋白的解析度为2.4。一项决议和 对其他结合蛋白的分析已经在进行中。相同 这项技术将被用来详细地确定 与这些结合蛋白结合的配体。构象变化随之而来 绑定，假定在移位中是必不可少的，并且是强制性的 在趋化行为期间信号传输的第一步，可以是 通过这一分析在dail中阐明了。我们还将采用停流 快速混合和小角X射线散射技术有待进一步研究 各种受体蛋白的连接状态。这项研究的结果 将从一个主要的分子基础上了解其作用 运输和趋化作用中的结合蛋白是两个重要的细胞 流程。运输过程在生物的生命中起着至关重要的作用 通过维持细胞内环境的相对恒定 并对各种物质的进入和存在进行管理 代谢活动。此外，趋化性对生存也很重要。 因为与环境的相互作用在很大程度上取决于 对刺激做出反应的能力。高等生物细胞的趋化性 对于受精和生物防御机制是重要的。此外， 信息的单一处理和传递原则 细菌在各种各样的感官系统中都是相似的。因此， 在相对简单的系统中详细了解这些流程 将允许在高等生物体中评估类似的过程和原理。

The long-range goal of this application is to study the structure and function of several periplasmic binding or receptor proteins. These proteins are essential components of osmotic shock-sensitive active transport and chemotaxis in bacteria. X-ray crystallography will be used primarily to ahcieve this goal. This goal is imminently possible since we have obtained single crystals of five receptor proteins specific for arabinose-, D-galactose-, maltose-, leucine/isoleucine/valine-, and sulfate-binding proteins. Furthermore, the crystal structure of the arabinose-binding protein has been solved at 2.4. A resolution and the analysis of other binding proteins are already in progress. The same technique will be utilized to determine in detail the stereochemistry of ligand binding to these binding proteins. Conformational changes attendant to binding, postulated to be essential in translocation and an obligatory first step in transmission of signals during chemotactic behavior, can be elucidated in dtail by this analysis. We will also employ stopped-flow rapid mixing and small angle x-ray scattering techniques to further study the liganded state of the various receptor proteins. Results of this study will from a major basis for a molecular understanding of the role of binding proteins in transport and chemotaxis, two important cellular processes. Transport processes perform a vital function in the life of the cell by maintaining a relative constancy of the environment within the cell and regulating the entrance and exist of various substances necessary for metabolic activity. In addition, chemotaxis is important for the survival of the microorgnisms since interaction with the environment depends largely on the ability to respond to stimuli. Taxis of cells from higher organisms is important for fertilization and biological defense mechanisms. Further, the principle of single processing and transmission of information in bacteria is similar in a wide variety of sensory systems. Therefore, detailed understanding of these processes in a relatively simple system will allow evaluation of similar process and principles in higher organisms.