Trehalose-6-phosphate phosphatase: a target for anti-onchocerciasis therapeutics

描述（由申请人提供）：寄生线虫导致非洲、亚洲和美洲的许多慢性失能和变形疾病。这些疾病包括淋巴丝虫病，这是一种蚊子传播的疾病，在81个国家流行。据估计，有1.2亿人感染了这种疾病。 对于寄生线虫是必需的但不具有人类同源物的酶是用于治疗干预的潜在药物靶标。来自B的基因组的可用性。马来丝虫是丝虫的代表性生物体，因此能够对这种寄生生物体的潜在药物靶点进行排序。 一种这样的酶是海藻糖-6-磷酸磷酸酶（T6 PP），其是海藻糖的生物合成所需的。T6 PP活性在C.通常用于寄生线虫的线虫模型最终导致生物体死亡，可能是由于海藻糖6-磷酸（T6 P）的积累。因为T6 PP是磷酸酶的卤代烷酸脱卤酶超家族的成员，所以关于该家族中的结构/功能关系的知识可用于定义用于药物开发的T6 PP。拟议的研究的目的是确定T6 PP活性位点区域的空间和静电特征，可以利用在铅抑制剂的设计。由于酶的两个结构域可以旋转以打开用于配体交换的活性位点，因此可以通过确定开放和封闭构象异构体的结构来获得抑制剂潜在靶向的表面积。 该研究计划集中在一个单一的目标：确定B类药物抑制剂开发的靶点。马来海藻糖-6-磷酸磷酸酶。将使用来自B的重组酶测定<$lead <$T6PP的X射线晶体结构。malayi和C. elegans来定义蛋白质的整体结构。共结晶和晶体浸泡实验将捕获闭合状态（使用无活性T6 PP突变体和T6 P或使用T6 PP加惰性底物类似物）和过渡态构象（T6 PP和海藻糖加钒酸盐、氟化铍或氟化铝）。结构-活性关系的分析将用于定义主导配体结合能贡献的结合相互作用。将确定开帽构象中酶的结构（使用apo T6 PP和T6 PP结构域-结构域结合突变体），以设计和评价可以填充和补充开帽构象异构体的扩展结合裂缝的双齿抑制剂。 这项工作将为开发用于治疗世界上大部分人口感染寄生线虫的疾病的药物奠定基础。

DESCRIPTION (provided by applicant): Parasitic nematodes are responsible for numerous chronically incapacitating and deforming diseases in Africa, Asia, and the Americas. Among these diseases is lymphatic filariasis, which is a mosquito-transmitted disease, endemic to 81 countries. It is estimated that 120 million people are infected with this disease. Enzymes that are essential for the parasitic nematodes but that do not have a human homologue are potential drug targets for therapeutic intervention. The availability of the genome from B. malayi, the representative organism for filarial nematodes, has enabled the ranking of potential drug targets from this parasitic organism. One such enzyme is trehalose-6-phosphate phosphatase (T6PP), which is required for the biosynthesis of trehalose. The oblation of T6PP activity in the C. elegans model commonly used for parasitic nematodes ultimately leads to organism death, probably due to the accumulation of trehalose 6-phosphate (T6P). Because T6PP is a member of the haloalkanoate dehalogenase superfamily of phosphatases, knowledge about the structure/function relationships in this family can be used to define T6PP for drug development. The objective of the proposed study is to identify the steric and electrostatic features of the T6PP active-site region that can be exploited in the design of lead inhibitors. Because the two domains of the enzyme can rotate to open the active site for ligand exchange, the surface area that can be potentially targeted by an inhibitor will be obtained by determining structures of bot open and closed conformers. The research plan is focused on a single Aim: Define the Target Site for the Development of Drug-like Inhibitors of B. malayi Trehalose-6-phosphate Phosphatase. The ¿lead¿ T6PP X-ray crystal structure will be determined using the recombinant enzyme from B. malayi and C. elegans to define the overall structure of the protein. Co-crystallization and crystal soaking experiments will capture the closed state (using an inactive T6PP mutant and T6P or using T6PP plus an inert substrate analog) and transition-state conformations (T6PP and trehalose plus vanadate, beryllium fluoride, or aluminum fluoride). Analysis of structure-activity relationships will be used to define the binding interactions which dominate the contributions to the ligand binding energy. The structure of the enzyme in the cap-open conformation will be determined (using apo T6PP and T6PP domain-domain binding mutants) in order to design and evaluate bidentate inhibitors that can fill and complement the expanded binding crevice of the cap-open conformer. This work will deliver the foundation for the development of a drug for the treatment of disease(s) inflicting the large segment of the world's population suffering from infection by parasitic nematodes.