FIBER DIFFRACTION FROM AMYLOID FILAMENTS

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 当蛋白质改变构象形成不溶性纤维时，就会形成淀粉样蛋白，从而导致严重的损伤和死亡。淀粉样变性包括阿尔茨海默病和朊病毒疾病，包括BSE（“疯牛病”）。哺乳动物朊病毒由PrP蛋白形成。淀粉样蛋白具有交叉β结构，但无法通过晶体学和NMR进行表征。纤维衍射为结构测定提供了最好的希望;样品制备和同步辐射的改进方法为获得改进的数据提供了前所未有的机会。结构研究需要回答基本的蛋白质折叠问题和药物设计。我们根据BioCAT/BioCARS协议于2009年10月和2010年8月在BioCARS收集数据，并于2010年4月在BioCAT收集数据。 我们收集了来自真菌朊病毒HET-s的数据（来自感染性HET-s的第一个高质量纤维衍射数据），来自低pH形式，以及来自在几种极端条件下形成的原纤维。这些数据表明，HET-s和其他淀粉样蛋白的多态性远远超过了人们所认识的，并且蛋白质可以随着时间的推移而改变形式。这一观察对于理解淀粉样蛋白及其相关疾病具有重要意义。 我们收集的数据，从21个残基片段的PrP，描述为传染性PrP的模型。 各种阿尔茨海默氏症相关肽A的制备似乎都产生相同的形式，与ssNMR报告的形式不同，尽管它是相关的。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Amyloids are formed when proteins change conformation to form insoluble fibers that cause severe damage and death. Amyloidoses include Alzheimer's and prion diseases including BSE ("mad cow disease"). Mammalian prions are formed by the protein PrP. Amyloids share a cross-beta structure, but have resisted characterization by crystallography and NMR. Fiber diffraction offers the best hope for structure determination; improved methods of specimen preparation and synchrotron radiation offer unprecedented opportunities to obtain improved data. Structural studies are needed to answer fundamental protein folding questions and for drug design. We collected data at BioCARS under the BioCAT/BioCARS agreement in October 2009 and August 2010, and at BioCAT in April 2010. We collected data from the fungal prion HET-s (the first good quality fiber diffraction data from infectious HET-s), from a low-pH form, and from fibrils formed under several extreme conditions. These data show that HET-s and other amyloids are far more polymorphic than had been realized, and that the protein can change form over time. This observation has great significance for understanding of amyloids in general, and for the diseases with which they are associated. We collected data from a 21-residue fragment of PrP, described as a model for infectious PrP. A variety of preparations of the Alzheimer's-associated peptide A¿ all appear to yield the same form, not identical to that reported from ssNMR, although it is related.