STRUCTURAL STUDIES OF PRION CONFORMATIONAL CONVERSION

朊病毒构象转化的结构研究

• 批准号: 7370439
• 负责人: SEBASTIAN DONIACH
• 金额: $ 0.02万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7370439
• 关键词: STRUCTURAL; STUDIES; PRION; CONFORMATIONAL; CONVERSION

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This proposal is to continue structural studies using small angle x-ray scattering (SAXS) on oligomeric forms of prion proteins which self associate as a result of conformational conversion from an alpha-helical form to a beta-rich form. Previous studies have led to the formulation of a "trimer-of-dimers" atomic scale model for a hexameric form of the mammalian recombinant PrP which can be compared directly with electron microscope data from negatively stained samples of the scrapie form of the protein obtained directly form animal brains. This comparison allows structural bounds to be placed on the differences between the non-infective recombinant form and the infective disease form. We plan to extend these studies by obtaining higher resolution data with the use of the CCD detector, and also to extend the studies to a protein , Sup-35, from yeast which has prion-like properties. and from which the existence of oligomeric intermediates along the folding pathway has been established by light scattering, em and afm work. We also plan to measure oligomeric forms of a protein fragment srcSH3 for which we have a series of alanine-replacement mutants. Following work of Dobson and collaborators, who have demonstrated that formation of amyloid fibrils appears to be a universal for self-association of polypeptides, we have shown that this protein forms fibrils after a lag phase. Study of the dependence of the formation of oligomers on point mutations, should help in validation of structural models for protein self-association such as domain swapping, or suggest new directions for understanding this fundamental phenomenon which is of importance in diseases such as Alzheimer's and Parkinson's.

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。这个建议是继续使用小角X射线散射（SAXS）的寡聚体形式的朊病毒蛋白的结构研究，作为构象转换的结果，从α-螺旋形式的β-丰富的形式自关联。以前的研究已经导致制定的“三聚体的二聚体”原子尺度模型的六聚体形式的哺乳动物重组PrP，可以直接与电子显微镜数据从负染色样品的羊瘙痒症形式的蛋白质直接从动物大脑中获得。这种比较允许将结构界限置于非感染性重组形式和感染性疾病形式之间的差异上。我们计划通过使用CCD检测器获得更高分辨率的数据来扩展这些研究，并将研究扩展到具有朊病毒样特性的酵母蛋白Sup-35。并且通过光散射、EM和AFM工作已经从其确定了低聚中间体沿着折叠途径的存在。我们还计划测量蛋白片段srcSH 3的寡聚体形式，为此我们有一系列丙氨酸置换突变体。在多布森和合作者的工作之后，他们已经证明淀粉样蛋白原纤维的形成似乎是多肽自缔合的普遍现象，我们已经证明这种蛋白质在滞后期后形成原纤维。研究寡聚体形成对点突变的依赖性，应该有助于验证蛋白质自缔合的结构模型，如结构域交换，或为理解这种在阿尔茨海默病和帕金森病等疾病中具有重要意义的基本现象提出新的方向。