Conformational heterogeneity and alpha-sheet: Determinants of toxicity in Abeta variants

淀粉样蛋白疾病涉及构象变化和正常可溶性肽和蛋白质的聚集。 当这些蛋白质改变开始错误折叠和聚集时，它们通过有毒的可溶性寡聚体阶段， 则它们最终形成不溶性原纤维。我们花了很多年的时间来描述这一时期的早期事件， 进展，并已观察到多种淀粉样蛋白相关肽之间的共同结构形式， 蛋白质尽管不同的一级和三级结构。我们“发现”的结构，我们称之为α-片层， 虽然在正常蛋白质中很少见，但在实验中观察到， 蛋白质数据库我们开始奋进设计和评估具有互补结构的小肽，也是α-折叠，以及它们在这些系统中抑制淀粉样蛋白形成的能力。这些从头设计的肽抑制多个不相关的淀粉样蛋白系统的聚集，表明我们正在靶向一个通用结构。当固定化时，这些设计还选择性地结合这些淀粉样蛋白的毒性寡聚体形式而不是单体或原纤维。在这里，我们建议通过调查与阿尔茨海默病相关的Abeta变体的淀粉样蛋白生成过程中是否形成α-折叠来扩展这些研究。然后，将在体外、神经母细胞瘤细胞和不同的、更具生物学相关性的系统中评价用从头α-折叠设计靶向毒性寡聚体的作用。

Amyloid diseases involve conformational changes and aggregation of normally soluble peptides and proteins. As these proteins change begin to misfold and aggregate they pass through a toxic soluble oligomer stage and then they ultimately form insoluble fibrils. We have spent many years characterizing the early events in this progression, and have observed a common structure form among multiple amyloid-associated peptides and proteins despite distinct primary and tertiary structure. The structure we “discovered”, which we call α-sheet, while rare in normal proteins, has been observed experimentally, and short stretches of α-strand are present in the Protein Data Bank. We embarked on an endeavor to design and evaluate small peptides with complementary structures, also α-sheets, and their ability to inhibit amyloid formation in these systems. These de novo designed peptides inhibit the aggregation of multiple unrelated amyloid systems, indicating that we are targeting a generic structure. When immobilized, these designs also selectively bind the toxic oligomeric forms of these amyloid proteins over the monomers or fibrils. Here we propose to extend these studies by investigating whether α-sheet forms during amyloidogenesis of Abeta variants associated with Alzheimer's disease. The effects of targeting the toxic oligomers with de novo α-sheet designs will then be evaluated in vitro, in neuroblastoma cells, and in different, more biologically relevant systems.