DRUG TARGETS OF OPPORTUNISTIC PATHOGENS IN AIDS

尽管机会性感染的治疗取得了进展，但 尽管如此，艾滋病仍然是发病率和死亡率的主要原因。测试 潜在的治疗药物因在治疗中的困难而困惑 许多这些病原体的培养和动物的不可靠 新代理测试中的模型。为了绕过这些 问题，我们计划克隆酶，这些酶是已知类别的 抗生素，大量异源表达这些蛋白 系统(如大肠杆菌和酵母菌)，并对其酶学特性进行了研究 目标的参数。表达的蛋白质及其序列将 为三维结构的测定和分析提供依据 目标的分子模型。结构信息将提供 为合理设计和鉴定药物奠定了基础。班级 具有新的必需的结构成分的化合物 将测试它们在体外抑制血管紧张素转换酶的有效性。 目标。 被选中进行研究的生物是卡氏肺孢子虫， 新生隐球菌和弓形虫。这些生物体导致 艾滋病患者中大部分危及生命的感染。我们的团队已经 卡氏肺孢子虫和新生隐球菌的治疗经验。许多. 为这项研究选定的目标已被分离并准备就绪 用于结构测定和分子建模。其他目标 鉴于我们在这一领域的经验，它们将很快被孤立。 选定的目标是叶酸和胸腺酸中的关键酶。 生物合成途径。因为抑制这一途径的药物已经 在卡氏肺孢子虫和弓形虫的临床应用中，我们知道 这些通路是化疗的合适靶点 干预。已选择的目标是二氢叶酸 二氢蝶呤合成酶(DHFR；甲氧苄氨嘧啶的靶标) (DHPs；磺胺靶标)和胸苷合成酶(TS；可能的 5-氟胞嘧啶的靶标)。丰富的运动构造信息是 可用于两种酶(TS和DHFR)，其中大部分已被 由这个组的成员决定。 该集团共同提供一个持续的药物开发系统，从 克隆到表达，到结构确定，再到分子建模。 该小组已经展示了之前的富有成效的互动。这种药 针对机会性病原体的靶点将不是一个全新的冒险，但 这些领域正在进行的项目的延伸。

Despite advances in the therapy of opportunistic infections complicating AIDS, they remain a leading cause of morbidity and mortality. Testing of potential therapeutic agents is confounded by the difficulties in the cultivation of many of these pathogens and the unreliability of animal models in the testing of new agents. In order to circumvent these problems, we plan to clone enzymes which are targets for known classes of antibiotics, expressing these proteins in large quantities in heterologous systems (e.g. E. Coli and yeast), and characterizing the enzymologic parameters of the targets. The expressed proteins and their sequences will provide the basis for the three-dimensional structure determination and molecular modeling of the targets. The structural information will provide the basis for rational drug design and identification. Classes of compounds which have the structural components necessary to be new inhibitors will be tested for their efficacy in the in vitro inhibition of the targets. The organisms that have been chosen for study are Pneumocystis carinii, Cryptococcus neoformans, and Toxoplasma gondii. These organisms cause the bulk of life-threatening infections in patients with AIDS. Our group has experience with Pneumocystis carinii and Cryptococcus neoformans. Many of targets selected for this study have already been isolated and are ready for structural determination and molecular modeling. The other targets will rapidly be isolated given our experience in this field. The targets chosen are crucial enzymes in the folate and thymidylate biosynthetic pathways. Since agents which inhibit this pathway are already in clinical use for Pneumocystis carinii and Toxoplasma gondii, we know that these pathways are appropriate targets for chemotherapeutic intervention. The targets that have been selected are dihydrofolate reductase (DHFR; the target of trimethoprim), dihydropteroate synthetase (DHPS; the sulfonamide target), and thymidylate synthase (TS; the likely target of 5-fluorocytosine). Abundant kinetic structural information is available for two these enzymes (TS and DHFR), much of which has been determined by members of this group. Together the group provides a continuous system of drug development from cloning to expression to structural determination to molecular modeling. The group has demonstrated previous productive interactions. The drug targets in opportunistic pathogens will not be an entirely new venture, but an extension of on-going projects in these fields.