THREE DIMENSIONAL MODELS FOR MEMBRANE RECEPTOR PROTEINS

整合膜受体蛋白通常在信号转导中起关键作用， 在细菌和高等生物中跨细胞膜转导 有机体 详细的三维结构知识， 这些受体蛋白无疑将大大有助于 信号分子机制的一般理解 转导，但艰巨的技术挑战禁止例行 确定大多数膜蛋白的高分辨率结构 目前。 因此，提出计算机建模研究， 生成细菌膜的详细三维模型 化学受体，来自大肠杆菌的Trg受体，以及许多 哺乳动物七螺旋G蛋白偶联受体，包括肾上腺素能受体 多巴胺神经递质受体和CCK-A肽受体。 肾上腺素能和多巴胺受体配体的几个具体问题 结合和选择性将利用分子建模来解决 技术和现有的实验数据。分子建模研究 并对CCK-A进行光亲和标记实验 与马约诊所的劳伦斯米勒教授合作， 以充分表征激动剂和拮抗剂结合位点。 最后一组 的建模研究将进行合作，教授。 华盛顿州立大学的Gerald Hazelbauer， 细菌Trg化学感受器的三维模型。利用 巯基可及性、交联和自旋标记的数据 Hazelbauer教授的小组进行的研究， 受体的跨膜和周质结构域将被 构建，以及与之相关的构象变化模型 将探索信号转导。模型结构将是 不断评估和完善使用新的实验数据教授。 海泽鲍尔的实验室详细的模型建立和 与实验小组的密切合作应该产生有用的新成果。 关于两种蛋白的结构和信号转导机制的信息 不同种类的膜受体蛋白。获得的信息 肾上腺素能、多巴胺和CCK-A受体也可用于 设计靶向这些受体的药理学试剂。

Integral membrane receptor proteins often play a key role in signal transduction across cell membranes in both bacteria and higher organisms. Detailed knowledge of the three-dimensional structures of these receptor proteins would undoubtedly contribute greatly to a general understanding of the molecular mechanisms of signal transduction, but formidable technical challenges prohibit the routine determination of high resolution structures for most membrane proteins at present. Therefore, computer modeling studies are proposed to generate detailed three-dimensional models for a bacterial membrane chemoreceptor, the Trg receptor from Escherichia coli, and a number of mammalian seven helix G protein-coupled receptors, including adrenergic and dopamine neurotransmitter receptors, and CCK-A peptide receptor. Several specific issues of adrenergic and dopamine receptor ligand binding and selectivity will be addressed utilizing molecular modeling techniques and existing experimental data. Molecular modeling studies and photoaffinity labeling experiments will be performed for CCK-A receptor, in collaboration with Prof. Laurence Miller at Mayo Clinic, to fully characterize agonist and antagonist binding sites. A final set of modeling studies will be undertaken in collaboration with Prof. Gerald Hazelbauer at Washington State University to generate detailed three-dimensional models for the bacterial Trg chemoreceptor. Utilizing data from sulfhydryl accessibility, crosslinking, and spin labeling studies performed by Prof. Hazelbauer's group, structures for the transmembrane and periplasmic domains of the receptor will be constructed, and models for the conformational changes associated with signal transduction will be explored. The model structures will be continually evaluated and refined using new experimental data from Prof. Hazelbauer's laboratory. The combination of detailed model building and close collaboration with experimental groups should yield useful new information about structure and signal transduction mechanisms for two distinct classes of membrane receptor proteins. Information obtained for the adrenergic, dopamine, and CCK-A receptors may also be of use in design of pharmacological agents targeted to these receptors.