Intermediate States of Aggregation-Prone Polypeptides

易聚集多肽的中间状态

• 批准号: 7059552
• 负责人: DARYL K EGGERS
• 金额: $ 12.29万
• 依托单位: SAN JOSE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7059552
• 关键词: alpha synuclein; amyloid proteins; bioenergetics; calorimetry; chemical aggregate; chemical hydration; circular dichroism; conformation; densitometry; intermolecular interaction; lysozyme; molecular pathology; peptides; protein folding; protein structure; protein structure function; thermodynamics

In the past decade, protein folding has gained wider recognition and acceptance as an important field of biomedical research due, in part, to the growing number of examples of protein misfolding that have been linked to human diseases. In most cases, the misfolding event results in the formation of intermolecular aggregates and higher-ordered structures, often leading to the characteristic plaques known as amyloid. One aim of this research is to monitor the changes in protein conformation that precede aggregation in a unique environment where intermolecular interactions are prohibited. This will be achieved by encapsulating aggregation-prone polypeptides in the pores of a silica glass matrix by the sol-gel technique. Once encapsulated, solvent conditions will be altered to mimic those conditions that favor aggregation in solution. Circular dichroism spectroscopy will be used to detect intermediate states that differ in conformation from both the native and aggregated states of each protein and to screen for drug candidates or solutes that destabilize the intermediate conformation. Lysozyme, alpha-synuclein, a peptide fragment from the yeast prion Sup35, and a disease-associated variant of CuZn-superoxide dismutase will be among the first polypeptides studied by this approach. A second major aim of this research is to determine whether unfavorable backbone hydration serves as a dominant force in aggregation of misfolded proteins. This goal involves the testing of a new thermodynamic framework, developed by this laboratory, that accounts for the participation of bulk water in aqueous equilibria. A combination of density measurements and calorimetry techniques will be used to calculate the free energy of the bulk aqueous phase in the presence of specific solutes. Calorimetry studies will be followed by solubility measurements of model amide-containing compounds to elucidate the magnitude of backbone solvation energetics in protein folding and aggregation. This project aims to further our understanding of factors that promote protein aggregation. This research could lead to new strategies for therapeutic intervention of diseases caused by misfolding of proteins, including Alzheimer's, Parkinson's, and Huntington's diseases.

在过去的十年中，蛋白质折叠作为蛋白质折叠的一个重要领域得到了更广泛的认可和接受。 生物医学研究，部分原因是越来越多的蛋白质错误折叠的例子， 与人类疾病有关。在大多数情况下，错误折叠事件导致形成分子间 聚集体和更高级的有序结构，通常导致称为淀粉样蛋白的特征性斑块。一 这项研究的目的是监测蛋白质构象的变化，在聚集之前，在一个独特的 分子间相互作用被禁止的环境。这将通过封装 通过溶胶-凝胶技术将易聚集多肽在二氧化硅玻璃基质的孔中。一旦 在包封的情况下，将改变溶剂条件以模拟有利于在溶液中聚集的那些条件。 圆二色性光谱将用于检测构象不同于 每种蛋白质的天然和聚集状态，并筛选 使中间构象不稳定。溶菌酶，α-突触核蛋白，一种来自酵母的肽片段 朊病毒Sup 35和与疾病相关的CuZn超氧化物歧化酶变体将是第一批 通过这种方法研究的多肽。 本研究的第二个主要目的是确定不利的主链水合作用是否作为 错误折叠蛋白质聚集的主导力量。这一目标涉及测试一种新的热力学 该框架，由该实验室开发，占散装水在水的参与 均衡密度测量和量热技术的组合将用于计算 在特定溶质存在下，本体水相的自由能。量热法研究将是 接着是模型含酰胺化合物的溶解度测量，以阐明 蛋白质折叠和聚集中的骨架溶剂化能量学。 该项目旨在进一步了解促进蛋白质聚集的因素。本研究 可能导致新的策略，用于治疗由蛋白质错误折叠引起的疾病， 包括阿尔茨海默氏症、帕金森氏症和亨廷顿氏症。