Molecular Mechanisms of Prion and Amyloid Propagation

朊病毒病是一组传染性神经退行性疾病，包括克雅氏病 人的瘙痒病和Gerstmann-Straussler-Scheinker（GSS）病，绵羊的瘙痒病，牛的瘙痒病， 牛的海绵状脑病（“疯牛病”）和鹿的慢性消耗病。最 这些疾病的有趣方面是感染性朊病毒病原体的性质， 具有淀粉样蛋白特征的错误折叠的蛋白质聚集体。然而，这些传染病的结构 蛋白质颗粒仍然是未知的。该项目的总体目标是获得高分辨率 结构洞察朊病毒繁殖的机制，以及朊病毒株的现象， 传播障碍。为此，我们使用了一个模型的淀粉样纤维产生的C-末端， 截短的朊病毒蛋白PrP 23 -144，一种与GSS样疾病的Y145 Stop表型相关的变体。 该模型的一个独特的优点是它可以在原子水平上进行详细的结构表征 通过固态核磁共振（NMR）光谱和其他生物物理技术。三 提出了相互关联的具体目标。第一个目标是确定高分辨率结构， 几种不同品系的小鼠和叙利亚仓鼠PrP 23 -144淀粉样蛋白原纤维，使用固态NMR。在 结合我们已经确定的人PrP 23 -144淀粉样蛋白的高分辨率结构， 这些数据将用于深入了解PrP淀粉样蛋白播种特异性的结构基础， 遗传障碍的体外替代物。在第二个目标中，我们将使用PrP 23 -144淀粉样蛋白模型， 阐明了朊病毒应变转换的知之甚少的现象以及应变的机制， 选择.最后，第三个目标是确定PrP淀粉样蛋白相关的高分辨率结构， 有不同的GSS疾病表型后一种见解具有根本的重要性，因为没有任何信息 目前关于GSS相关的PrP淀粉样蛋白的结构或 特定的结构特征和疾病表型。

Prion diseases are a group of transmissible neurodegenerative disorders that include Creutzfeldt-Jakob disease and Gerstmann-Straussler-Scheinker (GSS) disease in humans, scrapie in sheep, bovine spongiform encephalopathy (“mad cow disease”) in cattle and chronic wasting disease in cervids. The most intriguing aspect of these disorders is the nature of the infectious prion pathogen that is believed to be a misfolded protein aggregate with characteristics of an amyloid. However, the structure of these infectious protein particles remains largely unknown. The overall objective of this project is to gain high-resolution structural insight into the mechanism of prion propagation as well as the phenomena of prion strains and transmissibility barriers. To this end, we use a model of amyloid fibrils generated from the C-terminally truncated prion protein PrP23-144, a variant associated with the Y145Stop phenotype of a GSS-like disease. A unique advantage of this model is that it is amenable to detailed structural characterization at atomic level by solid-state nuclear magnetic resonance (NMR) spectroscopy and other biophysical techniques. Three interrelated specific aims are proposed. The first aim is to determine the high-resolution structures for several different strains of mouse and Syrian hamster PrP23-144 amyloid fibrils using solid-state NMR. In combination with the high-resolution structure of human PrP23-144 amyloid already determined by us, these data will be used to gain insight into the structural basis of PrP amyloid seeding specificities, an in vitro surrogate of transmissibility barriers. In the second aim, we will use the PrP23-144 amyloid model to elucidate the poorly understood phenomenon of prion strain switching as well as the mechanism of strain selection. Finally, the third aim seeks to determine high-resolution structures of PrP amyloids associated with distinct phenotypes of GSS disease. The latter insight is of fundamental importance, as no information is at present available regarding the structures of GSS-associated PrP amyloids or the relationship between specific structural features and disease phenotype.