Structural biology of yeast prions.

描述（由申请人提供）：朊病毒是几种致命性神经退行性疾病的基础，如人类的克雅氏病、牛的疯牛病和羊瘙痒病。在酵母中，朊病毒被发现是几种非孟德尔表型的基础。尽管序列不同，但酵母朊病毒与人类朊病毒具有相似的特征，包括感染性，朊病毒应变现象和物种屏障。因此，酵母朊病毒是研究朊病毒疾病机制的理想模型系统。人类朊病毒疾病的几个关键方面是明确说明使用酵母朊病毒，包括蛋白质唯一的假说，构象变异作为基础的朊病毒株， 伴侣的参与。朊病毒领域的一个知识空白是缺乏朊病毒原纤维的详细高分辨率结构。在这个项目中，我们的目标是确定原纤维结构的酵母朊病毒蛋白尿素2，最好的研究酵母朊病毒之一，在静止和搅拌条件下。已经提出，不同的原纤维结构是不同朊病毒株的基础。我们的初步研究表明，尿素纤维确实采取不同的结构在静止和搅拌条件下。在这两种条件下的Ure 2原纤维的全原子结构模型将带来对朊病毒株的结构基础和朊病毒繁殖机制的深入了解。该项目包括三个具体目标。在目标1中，我们将在静止和搅拌条件下确定Ure 2原纤维中的半链和转角/环区域。在目标2中，我们将获得静止和搅拌的Ure 2原纤维的一组广泛的残基间距离约束。在目标3中，我们将使用实验约束和结构预测程序Rosetta来计算静止和搅动的Ure 2原纤维的原子水平结构模型。

DESCRIPTION (provided by applicant): Prions are the basis of several fatal neurodegenerative disorders such as Creutzfeldt-Jakob disease in humans, mad cow disease in cattle, and scrapie in sheep. In yeast, prions have been found to underlie several non-Mendelian phenotypes. Despite differences in sequence, yeast prions share similar features with human prions including infectivity, prion strain phenomenon, and species barrier. Therefore, yeast prions are excellent model systems to study the mechanism of prion diseases. Several key aspects of human prion diseases are unambiguously illustrated using yeast prions, including the protein only hypothesis, conformational variations as the basis of prion strains, and involvement of chaperones. A knowledge gap in the prion field is the lack of detailed high-resolution structures for prion fibrils. In this project, we aim to determine fibril structures of he yeast prion protein Ure2, one of the best studied yeast prions, under quiescent and agitated conditions. It has been proposed that different fibril structures are the basis of different prion strains. Our preliminary studies have shown that Ure2 fibrils indeed adopt different structures under quiescent and agitated conditions. Full- atom structural models of Ure2 fibrils under these two conditions will bring insights into the structural basis of prion strains and mechanism of prio propagation. This project consists of three specific aims. In Aim 1, we will determine the ¿-strand and turn/loop regions in Ure2 fibril under quiescent and agitated conditions. In Aim 2, we will obtain an extensive set of inter-residue distance constraints for quiescent and agitated Ure2 fibrils. In Aim 3, we will use the experimental constraints and structure prediction program Rosetta to calculate atomic- level structure models for quiescent and agitated Ure2 fibrils.