Prenyldiphosphate Synthase Inhibitors: Novel Anti-Infective Agents

描述（由申请人提供）：这项工作的总体目标是通过结合x射线晶体学、核磁共振光谱、量热法、酶和细胞生长抑制试验、定量构效关系技术、量子化学、合成、给药和动物实验，开发针对原生动物和细菌中异戊二烯生物合成途径的新型抗感染药物。第一个具体目标是使用x射线晶体学和固态核磁共振光谱来研究主要结合克氏锥虫（美洲锥虫病或恰加斯病的病原体）、布鲁氏锥虫（非洲昏睡病的病原体）、大肠杆菌和金黄色葡萄球菌以及人类FPPS（用于治疗骨吸收疾病的双膦酸盐药物的靶标）的新型抑制剂的结构。在设计抑制剂选择性的背景下感兴趣)。固态核磁共振将通过提供动力学（来自2H核磁共振）和质子化状态信息（来自13C， 15N， 31P化学位移）来补充晶体学结果，用于QSAR研究。第二个具体目标是研究结构-功能关系。我们将通过等温滴定量热法和差示扫描量热法以及经典的酶抑制技术来研究抑制剂的结合，从而推断出在Aim 1中研究的系统的配体结合常数（KB）和Kis以及结合信息的热力学。此外，抑制剂与人类骨骼和骨矿物质模型的结合将使用色谱和核磁共振技术进行研究。这些结果都将通过QSAR方法进行分析，包括使用差分QSAR方法（优化寄生虫/细菌抑制与人类FPPS抑制，并最大限度地减少骨骼吸附），以及使用非常规QM描述符和2H NMR顺序参数，以增强这些方法的预测功能。第三个也是最后一个特定目标是利用目标1和目标2的结果设计并合成异戊二烯生物合成途径的特异性抑制剂。这些抑制剂将包括新的吡啶、磺胺和磷，并将被设计用于在原生动物和细菌酶的活性位点上发现独特的极性残基。然后将这些抑制剂配制成生物可利用的形式用于动物试验。我们还将关注使用两种或三种化合物的协同或联合治疗方法，每种化合物都针对异戊二烯生物合成途径：已经观察到这种强烈的协同相互作用，现在需要使用新型抑制剂进行优化。摘要：这项研究的目的是找到新的治疗方法来治疗各种传染病。在美国，这些疾病主要是细菌性的，是一个主要的公共卫生威胁，而在世界其他地方，传染病主要是由原生动物引起的。这项工作旨在开发治疗这两种疾病的药物。

DESCRIPTION (provided by applicant): The broad, overall objective of this work is to develop novel anti-infective agents which target the isoprene biosynthesis pathways in protozoa and bacteria by using a combination of x-ray crystallography, NMR spectroscopy, calorimetry, enzyme and cell growth inhibition assays, QSAR (quantitative structure-activity relationship) techniques, quantum chemistry, synthesis, drug delivery and animal testing. The First Specific Aim is to use x-ray crystallography and solid-state NMR spectroscopy to investigate the structures of novel inhibitors bound to, primarily, farnesyl diphosphate synthase (FPPS) from Trypanosoma cruzi (the causative agent of American trypanosomiasis or Chagas disease), Trypanosoma brucei (the causative agent of African sleeping sickness), E. coli and Staphylococcus aureus, as well as human FPPS (the target for the bisphosphonate drugs used in treating bone resorption diseases, of interest in the context of designing inhibitor selectivity). Solid-state NMR will be used to complement the crystallographic results by providing dynamics (from 2H NMR) and protonation state information (from 13C, 15N, 31P chemical shifts) for use in the QSAR investigations. The Second Specific Aim is to investigate structure-function relationships. We will investigate inhibitor binding by using isothermal titration calorimetry and differential scanning calorimetry, as well as by using classical enzyme inhibition techniques, to deduce ligand binding constants (KB) and Kis together with thermodynamics of binding information for the systems studied in Aim 1. In addition, inhibitor binding to human bone and bone mineral models will be investigated using chromatographic and NMR techniques. These results will all then be analyzed by using QSAR methods, including the use of differential QSAR methods (to optimize parasite/bacterial inhibition versus human FPPS inhibition, and to minimize bone adsorption), together with the use of non-conventional QM descriptors and 2H NMR order parameters, to enhance the predictive utility of these methods. The Third and Final Specific Aim is to use the results from Aims 1 and 2 to design and then synthesize specific inhibitors of the isoprene biosynthesis pathway. These inhibitors will include novel pyridium, sulfonium and phosphonium species and will be designed to target unique polar residues found in the active site of the protozoal and bacterial enzymes. These inhibitors will then be formulated in bioavailable forms for use in animal testing. We will also focus on synergistic or combination therapy approaches by using two or three compounds, each of which target the isoprene biosynthesis pathway: such strongly synergistic interactions have already been observed and now need to be optimized using the novel inhibitors. Lay Summary: The research proposed is designed to lead to new therapeutic approaches to treat a variety of infectious diseases. In the US, these diseases are primarily bacterial and are a major public health threat while in the rest of the world, infectious diseases are mainly caused by protozoa. This work seeks to develop drugs to treat both sorts of disease.