AIDS RELATED NMR RESEARCH

这个项目有几个组成部分：1.我们正在使用核磁共振光谱学来表征人类免疫缺陷病毒功能所需的蛋白质。在过去的一年里，我们开始了一个项目，准备同位素标记的逆转录酶，这是从病毒RNA合成细胞DNA所需的蛋白质。同位素标记的使用将使我们能够探测酶中对活性和药物相互作用重要的位置。2.我们最近发展了一种用于分析配体与大分子结合的核磁共振方法。这些研究寻找与附近位置的大分子靶标结合的配位体对。通过选择相互结合紧密的配体，可以通过化学结合这些配体来设计更有效的抑制剂。我们将把这种方法应用于逆转录酶抑制剂的开发。3.免疫系统受损的患者更容易受到外来细菌感染，导致对抗生素治疗的依赖增加。细菌对抗叶酸药物治疗的耐药机制之一是表达一种质粒II型二氢叶酸还原酶，该酶在结构上与染色体上的DHFR无关，对甲氧普林等细菌抗叶酸具有耐药性。我们一直在研究II型DHFR与配体的相互作用，以了解其催化机理，并开发新的抑制剂。观察到连接吡啶核苷酸和叶酸质子的配体间Overhaser效应，并用于定义三元络合物的结构。

This project has several components: 1. We are using NMR spectroscopy to characterize proteins required for the functioning of the human immunodeficiency virus. During the past year, we began a program for the preparation of isotopically labeled reverse transcriptase, the protein required for the synthesis of cellular DNA from the viral RNA. The use of isotopic labels will allow us to probe positions in the enzyme important for activity and drug interactions. 2. We have recently developed an NMR approach for the analysis of ligand binding to macromolecules. These studies look for pairs of ligands which bind to a macromolecular target at nearby sites. By selecting ligands which bind near to each other, it is anticipated that it will be possible to design more potent inhibitors by chemically combining these ligands. We will be applying this approach to the development of reverse transcriptase inhibitors. 3. Patients with a compromised immune system are more susceptible to adventitious bacterial infections, leading to increased dependence on antibiotic treatments. One mechanism of bacterial resistance to anti-folate drug therapy involves the expression of a plasmid type II dihydrofolate reductase, which is structurally unrelated to chromosomal DHFR and is resistant to bacterial antifolates such as trimethoprim. We have been studying the interaction of the type II DHFR with ligands in order to understand the catalytic mechanism and to develop new inhibitors. Inter-ligand Overhaser effects connecting the pyridine nucleotide and folate protons were observed and are being used to define a structure of the ternary complex.