Structural biology of yeast prions.

描述(申请人提供)：蛋白是几种致命性神经退行性疾病的基础，如人类的克雅氏病、牛的疯牛病和绵羊的瘙痒病。在酵母中，已经发现了几种非孟德尔表型的普鲁恩基因。尽管在序列上有所不同，但酵母蛋白与人类蛋白有相似的特征，包括感染性、蛋白菌株现象和物种屏障。因此，酵母Pron是研究Pron病发病机制的良好模型系统。几个关键方面的人类普鲁恩疾病明确说明了酵母普恩，包括纯蛋白质的假说，构象变化作为普恩菌株的基础，以及 监护人的参与。普里子领域的一个知识空白是缺乏普里恩纤维的详细的高分辨率结构。在这个项目中，我们的目标是在静止和搅拌的条件下，测定研究得最好的酵母蛋白之一--酵母胶原蛋白Ure2的纤维结构。有人提出，不同的纤毛结构是不同的Pron菌株的基础。我们的初步研究表明，在静止和搅拌条件下，Ure2纤维确实具有不同的结构。这两种情况下的Ure2原纤的全原子结构模型将有助于深入了解PrIO的结构基础和PrIO的传播机制。该项目由三个具体目标组成。在目标1中，我们将确定Ure2原纤维在静止和搅拌条件下的单链和转角/环区域。在目标2中，我们将为静止和搅拌的Ure2纤维获得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来计算静止和搅拌的Ure2纤维的原子级结构模型。

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.