NMR STUDIES OF BIOMOLECULAR STRUCTURE, FUNCTION AND DYNAMICS

我们继续努力修改和改进核磁共振方法，以 共振峰的归属和分子结构的分析 动力学，并将这些方法应用于与以下相关的问题 环境健康。分析中固有的中心问题之一 使用核磁共振的复杂分子是导致光谱的复杂性 来自大量的重叠共振。以下是几个新的战略 获得经过编辑的二维核磁共振谱，克服了限制 由大量的共振产生的结果已经在 过去的一年。与DTRT的莫罗·汤普森博士合作，其中一些 方法已应用于胆汁酸加合物的分析 用α-萘基异硫氰酸酯(ANIT)处理大鼠后 会导致胆管坏死。两项新的结构核磁共振研究，都是 在过去的一年里，还启动了与艾滋病相关的研究。这个 首先是与罗伯特·汉舒马赫博士就 免疫抑制药物的明显靶点--亲环素 环孢菌素A最近被证明亲环素催化 肽基-脯氨酸键的顺式/反式异构化； 这种酶在生理上的重要靶点尚未确定。 有观点认为，生物活性多肽缓激肽可能是一种 该酶的底物和缓激肽的氟化类似物 是由约翰·斯图尔特博士准备的 科罗拉多大学。已经确定顺式/反式 缓激肽及其[Gly6]-缓激肽的异构化速率常数 类似物在酶的存在下显著增加。一秒钟 在过去一年内展开的结构性研究旨在确定 嘌呤核苷磷酸化酶抑制剂的构象 (PNPase)，它在核苷类药物的分解代谢中起重要作用 治疗各种疾病，以及在合成这些 毒品。

We have continued our efforts to modify and improve NMR methodologies for the assignment of resonances and the analysis of molecular structure and dynamics, and to apply these approaches to problems related to environmental health. One of the central problems inherent in the analysis of complex molecules using NMR is the complexity of the spectra resulting from the large number of overlapping resonances. Several new strategies for obtaining edited 2-dimensional NMR spectra which overcame the limitations resulting from the large number of resonances have been evaluated over the past year. In collaboration with Dr. Morrow Thompson of DTRT, some of these methods have been applied to the analysis of bile acid adducts obtained subsequent to the treatment of rats with a-naphthyl isothiocyanate (ANIT) which causes bile duct necrosis. Two new structural NMR efforts, both related to AIDS research, were also initiated during the past year. The first is a collaborative effort with Dr. Robert Handschumacher on the enzyme cyclophilin, the apparent target of the immunosuppressive drug cyclosporin A. It has recently been demonstrated that cyclophilin catalyzes the cis/trans isomerization of peptidyl-proline bonds; however, the physiologically important targets of this enzyme have yet to be identified. It was proposed that the biologically active peptide bradykinin might be a substrate for this enzyme, and fluorinated analogs of bradykinin which can be monitored with fluorine-19 NMR were prepared by Dr. John Stewart of the University of Colorado. It has been determined that the cis/trans isomerization rate constants of both bradykinin and its [Gly6]-bradykinin analog are significantly increased in the presence of the enzyme. A second structural study initiated during the past year is aimed at determining the conformation of inhibitors of the enzyme purine nucleoside phosphorylase (PNPase), which is important in the catabolism of nucleoside drugs used to treat a variety of illnesses, as well as in the synthesis of the these drugs.