Structure and Inhibition of Amyloid in Alzheimer's Disease

我们的假设是，缺乏治疗阿尔茨海默病的药物在很大程度上是由于无知 最相关的药物靶点的结构：tau和tau蛋白的聚集形式 β-淀粉样蛋白。在这里，我们建议扩大我们对淀粉样蛋白纤维结构和 低聚物可实现抑制化合物的基于结构的设计。对于我们建议的每一项 在项目中，在确定结构之后将进行基于结构的一种或多种抑制剂的设计。 然后，将测试每个抑制剂在体外抑制聚集形成的有效性，并 在细胞模型中抑制毒性。然后将在动物模型中评估最有效的抑制剂 我们的合作者。我们的项目包括：(1)确定能使tau在细胞间扩散的tau寡聚体的结构，并随后设计一种寡聚抑制剂；(2)基于我们新确定的淀粉样蛋白形成结构设计tau聚集的抑制剂。 带有VQIINK序列的tau片段；(3)核糖体显示抑制单域的进化 针对tau聚合体的抗体，这些抗体可能会穿透血脑- (4)用序列优化现有的β-淀粉样蛋白20个残基片段的晶体 GKLVFFGENVGSNKGAIIGL，似乎形成了一种低聚物。改进的晶体将紧随其后 通过结构确定和抑制剂设计；(5)β-淀粉样蛋白或其片段的结晶 脂质环境，以了解其毒性功能；(6)一种 β-淀粉样蛋白片段与其假定的细胞表面受体结合，随后进行抑制物设计；(7) 我们新发现的转甲状腺素蛋白断裂片段的作用探讨 上调β-淀粉样蛋白的寡聚体并抑制毒性。这些项目中的每一个，如果成功，都为可能的阿尔茨海默病治疗剂开辟了一条道路。这些路径以前是不可用的，因为相关结构一直未知。我们发现确定淀粉样蛋白结构的主要障碍是晶体的微小尺寸。我们建议通过进一步开发先进的电子衍射方法来克服这一障碍。

Our hypothesis is that the lack of drugs to halt Alzheimer’s disease stems in large part from ignorance of the structures of the most pertinent drug targets: the aggregated forms of the proteins tau and beta-amyloid. Here we propose to extend our studies of the structures of amyloid fibrils and oligomers to enable structure-based design of inhibiting compounds. For each of our proposed projects, structure determination will be followed by structure-based design of one or more inhibitors. Then each inhibitor will be assayed for effectiveness in inhibiting aggregate formation in vitro and inhibiting toxicity in cell models. The most effective inhibitors will then be assessed in animal models of our collaborators. Among our projects are the following: (1) Structure determination of oligomers of tau that can seed spreading of tau from cell to cell, and subsequent design of an inhibitor of oligomerization; (2) Inhibitor design of tau aggregation based on our newly determined structure of the amyloid-forming segment of tau with sequence VQIINK; (3) Evolution by ribosome display of inhibiting single-domain antibodies against tau aggregates, with the possibility that these may penetrate the blood-brain- barrier; (4) Optimization of existing crystals of the 20 residue segment of beta-amyloid with sequence GKLVFFGENVGSNKGAIIGL, which seems to form an oligomer. Improved crystals will be followed by structure determination and inhibitor design; (5) Crystallization of beta-amyloid or its segments in a lipid environment to gain possible insight into its toxic function; (6) Structure determination of a segment of beta-amyloid bound to its putative cell-surface receptor, followed by inhibitor design; (7) Exploration of the action of our newly discovered segment of the protein transthyretin which breaks up oligomers of beta-amyloid and inhibits toxicity. Each of these projects, if successful, opens a path to a possible therapeutic agent against Alzheimer’s disease. These paths have not been previously available because the pertinent structures have been unknown. We find the principal barrier to determination of amyloid structures is the miniscule size of the crystals. We propose to surmount this barrier by further exploitation of advanced methods of electron diffraction.