Discovery of West Nile Virus Protease Inhibitors

描述（由申请人提供）：目前在美国大陆流行的西尼罗河病毒株比最初在非洲分离的病毒毒力更强，被NIAID归类为B类优先病原体。在短短六年内，它已经蔓延到整个美国大陆，导致高发病率和死亡率。去年，在向CDC报告的2，539例病例中，近一半的患者有神经侵入性症状。目前没有疫苗或药物可以对抗西尼罗河病毒感染，只能对症治疗。我们的最终目标是开发一种预防或治疗这种疾病的方法。为了实现这一目标，我们将开发用于鉴定抑制西尼罗病毒NS3蛋白酶的化合物的方法。蛋白酶是病毒成熟的关键酶，并且黄病毒蛋白酶的抑制已显示出显著减少病毒复制。基于结构的药物设计将提供一个快速的途径，有效的和病毒特异性蛋白酶抑制剂。在存在和不存在已知的基于肽的抑制剂的情况下，该蛋白酶的晶体结构将被确定以表征活性位点。我们将用化学文库来虚拟筛选活性位点。将仔细注意库的组成，以确保丰富多样的，具有生物活性的，铅样化合物。将开发一种具有广泛灵敏度的生化测定法，可用于从我们的虚拟筛选中识别弱结合初始命中，以及在我们在未来研究中优化这些命中时测量抑制的微小变化。在虚拟筛选中选择的并且在生化测定中具有活性的化合物将与蛋白酶共结晶，从而使我们清楚地了解化合物与活性位点的匹配情况。这将使我们能够从活性化合物中快速识别出最佳候选物，并在第二阶段研究中进行后续优化。

DESCRIPTION (provided by applicant): The strain of West Nile virus now endemic in the continental United States is more virulent than the virus originally isolated in Africa and is classified as a category B priority pathogen by the NIAID. In only six years, it has spread throughout the continental United States, resulting in high morbidity and mortality. Last year, of the 2,539 cases reported to the CDC, nearly half of the patents had neuroinvasive symptoms. There is currently no vaccine or drug that combats the West Nile virus infection and only symptomatic treatment is available. Our ultimate goal is to develop a prophylactic or therapeutic treatment for this disease. To accomplish this, we will develop methods for the identification of compounds that inhibit the West Nile viral NS3 protease. The protease is a key enzyme in viral maturation and inhibition of flavivirus protease has been shown to dramatically reduce viral replication. Structure based drug design will provide a rapid path to potent and virus specific protease inhibitors. The crystal structure of this protease in the presence and absence of known peptide based inhibitors will be determined in an effort to characterize the active site. We will virtually screen the active site with a chemical library. Careful attention will be made to the composition of the library to ensure enrichment with diverse, pharmacologically active, lead-like compounds. A biochemical assay will be developed that has a wide range of sensitivity that can be used in the identification of weak binding initial hits from our virtual screen as well as to measure small changes in inhibition as we optimize these hits in future research. Compounds that are selected in the virtual screen and are active in the biochemical assay will be cocrystallized with the protease, giving us a clear picture of the compound's fit into the active site. This will position us to rapidly identify the best candidates from the active compounds and subsequent optimization in phase 2 research.