Prenyldiphosphate Synthase Inhibitors: Novel Anti-Infective Agents

描述（由申请人提供）：本工作的广泛总体目标是开发新型抗感染剂，其通过使用X射线晶体学、NMR光谱学、量热法、酶和细胞生长抑制测定、QSAR（定量结构-活性关系）技术、量子化学、合成、药物递送和动物试验的组合靶向原生动物和细菌中的异戊二烯生物合成途径。第一个具体目标是使用X射线晶体学和固态NMR光谱来研究主要与来自克氏锥虫（美洲锥虫病或恰加斯病的病原体）、布氏锥虫（非洲昏睡病的病原体）、E.大肠杆菌和金黄色葡萄球菌，以及人FPPS（用于治疗骨吸收疾病的双膦酸盐药物的靶标，在设计抑制剂选择性的背景下感兴趣）。固态NMR将通过提供用于QSAR研究的动力学（来自2 H NMR）和质子化状态信息（来自13 C，15 N，31 P化学位移）来补充晶体学结果。第二个具体目标是研究结构-功能关系。我们将研究抑制剂结合，通过使用等温滴定量热法和差示扫描量热法，以及通过使用经典的酶抑制技术，推导配体结合常数（KB）和Kis与热力学的结合信息的系统中研究的目的1。此外，将使用色谱和NMR技术研究抑制剂与人骨和骨矿物质模型的结合。然后将通过使用QSAR方法分析所有这些结果，包括使用差分QSAR方法（以优化寄生虫/细菌抑制与人FPPS抑制，并最大限度地减少骨吸附），以及使用非常规QM描述符和2 H NMR顺序参数，以增强这些方法的预测效用。第三个也是最后一个具体目标是使用目标1和2的结果来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，锍和磷物种，并将被设计为目标的原生动物和细菌酶的活性位点中发现的独特的极性残基。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，每种化合物都靶向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。概述：这项研究旨在为治疗各种传染病提供新的治疗方法。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，而在世界其他地区，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.