INHIBITION AND MECHANISM OF AMYLOID BETA-AGGREGATION

β淀粉样蛋白聚集的抑制及其机制

• 批准号: 6509819
• 负责人: MICHAEL Gerard ZAGORSKI
• 金额: $ 22.35万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6509819
• 关键词: aging; amyloid proteins; amyloidosis; apolipoprotein E; biophysics; carbon; chemical aggregate; chemical association; conformation; cytotoxicity; inhibitor /antagonist; molecular dynamics; molecular pathology; neurofibrillary tangles; nitrogen; nuclear magnetic resonance spectroscopy; protein structure function; stable isotope; water solution

Description (From the applicant's abstract): The neuropathological hallmarks of Alzheimer's disease (AD) are the abundance of intraneuronal neurofibrillary tangles and the extracellular deposition of the Abeta peptide as amyloid plaques. Extensive genetic and cell viability studies support a key role for the Abeta peptide in AD neurodegeneration. The Abeta pathologic effects are related to the formation of insoluble aggregates dominated by beta-sheet structures. Biochemical studies suggest that the longer, 42-residue Abeta (1-42) is more pathogenic than the shorter, 40-residue Abeta (1-40), due to its greater in vitro tendency to aggregate and precipitate as amyloid. Nonetheless, a molecular basis for the greater pathogenicity of the Abeta (1-42) has yet to be determined. Our laboratory is one of the few research groups that has successfully applied high-resolution NMR methods to study the structure and aggregational properties of the Abeta peptides. The NMR approach is extremely powerful for studying proteins, in that it can detect site-specific aspects of the structures and dynamics in solution at the atomic level. Using NMR, we have discovered differences between the monomeric forms of the Abeta (1-40) and Abeta (1-42) in water solution at pH 7.2, in which the Abeta (1-42) displayed multiple NH peaks for Val36, Gly37, Gly38, and Val39, a region previously implicated to contain a cis peptide bond that could be important for initiating beta-amyloidosis. Our NMR results may account for the greater beta-aggregation of the Abeta (1-42), and we hypothesize that the monomeric Abeta (1-42) adopts a unique structure not present for monomeric Abeta (1-40). This application contains three well-coupled, specific aims. The first aim will be to explore the effects of D-Asp, D-Ser and iso-Asp on the structure and beta-aggregation rates of the Abeta (1-42). We hypothesize that these permutations alter the structure in a manner to create a seed" that nucleates beta-amyloidosis. Aim 2 will examine the dynamics of the Abeta association in aqueous solution using 15N and 13C NMR relaxation studies. We will carefully compare the site-specific association of the Abeta (1-40) and Abeta (1-42), and determine if cis-trans isomerization occurs at the Gly37-Gly38 peptide bond for monomeric Abeta (1-42). To locate putative inhibitor bindings sites or surfaces, Aim 3 will conduct NMR binding studies with macromolecules (such as ApoE and ApoJ) and presumed amyloid inhibitors with monomeric Abeta (1-40) and Abeta (1-42). This information has potential for additives and drug candidates to interfere with the beta-aggregation process and provide detailed structural information about the biding mode of amyloid inhibitors. With these data, a more rational approach to the design of less toxic and more effective inhibitors of beta-amyloidosis will be explored by collaboration with scientists in the medical school.

描述（来自申请人的摘要）：神经病理学特征 阿尔茨海默氏病（AD）是神经元内神经原纤维的丰富 缠结和 Abeta 肽作为淀粉样蛋白的细胞外沉积 牌匾。广泛的遗传和细胞活力研究支持关键作用 AD 神经变性中的 Abeta 肽。 Abeta 的病理效应是 与以 β-折叠为主的不溶性聚集体的形成有关 结构。生化研究表明，较长的 42 个残基 Abeta (1-42) 比较短的 40 个残基 Abeta (1-40) 更具致病性，因为它 体外以淀粉样蛋白形式聚集和沉淀的倾向更大。尽管如此， Abeta (1-42) 更强致病性的分子基础尚未确定 被确定。 我们实验室是为数不多的已成功应用的研究组之一 高分辨率核磁共振方法研究结构和聚集特性 Abeta 肽。 NMR 方法对于研究来说非常强大 蛋白质，因为它可以检测结构的位点特定方面， 原子水平上溶液的动力学。使用核磁共振，我们发现 Abeta (1-40) 和 Abeta (1-42) 单体形式之间的差异 pH 7.2 的水溶液，其中 Abeta (1-42) 显示多个 NH 峰 对于 Val36、Gly37、Gly38 和 Val39，先前暗示包含 顺式肽键对于启动β-淀粉样变性可能很重要。我们的 NMR 结果可能解释了 Abeta (1-42) 更大的 β 聚集， 我们假设单体 Abeta (1-42) 采用独特的结构 单体 Abeta (1-40) 不存在。 该应用程序包含三个耦合良好的具体目标。第一个目标将 探讨D-Asp、D-Ser和iso-Asp对结构和结构的影响 Abeta (1-42) 的 beta 聚集率。我们假设这些 排列改变结构的方式是创造出“种子”，从而成核 β-淀粉样变性。目标 2 将检查 Abeta 协会的动态 使用 15N 和 13C NMR 弛豫研究对水溶液进行分析。我们会用心 比较 Abeta (1-40) 和 Abeta (1-42) 的位点特异性关联，以及 确定 Gly37-Gly38 肽键是否发生顺反异构化 单体 Abeta (1-42)。定位假定的抑制剂结合位点或 表面，Aim 3 将进行 NMR 与大分子的结合研究（例如 ApoE 和 ApoJ) 和推测的具有单体 Abeta (1-40) 的淀粉样蛋白抑制剂和 阿贝塔（1-42）。该信息对于添加剂和候选药物具有潜力 干扰β聚合过程并提供详细的结构 有关淀粉样蛋白抑制剂的结合模式的信息。有了这些数据，一个 更合理的设计方法，毒性更小，更有效 β-淀粉样变性抑制剂将通过与 医学院的科学家。