PHYSICAL BIOCHEMISTRY AND BIOLOGY OF AMYLOID B-PROTEIN

B 淀粉样蛋白的物理生物化学和生物学

• 批准号: 7112180
• 负责人: DAVID B. TEPLOW
• 金额: $ 19.74万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7112180
• 关键词: Alzheimer' s disease; acyl group; amyloid proteins; amyloidosis; cerebral degeneration; chemical kinetics; conformation; hydropathy; ionic bond; light scattering; mass spectrometry; molecular dynamics; molecular pathology; neuropathology; neurotoxins; oligopeptides; organic brain syndrome; peptide chemical synthesis; protein folding; protein structure function; thermodynamics

In Alzheimer's disease (AD), progressive deposition of amyloid beta-protein (Abeta) fibrils, "amyloid plaques," occurs in the brain. However, neuronal dysfunction may occur prior to plaque formation. Structure-neurotoxicity studies have revealed progressively smaller toxic assemblies, including protofibrils, paranuclei, and ADDLs. In rodents, Abeta oligomers can inhibit long-term potentiation (LTP), a model for learning and memory. In AD patients, Abeta oligomers are present in levels significantly greater than in agematched normal individuals. Biophysical, cell culture, animal, and human studies thus all support the hypothesis that oligpmerization of Abeta is a key event in AD pathogenesis. If so, then the development of therapeutic strategies depends on elucidation of the mechanism(s) of pathologic protein folding, oligomerization, and higher-order assembly. Continuing efforts in our laboratory to understand the earliest steps in Abeta assembly, Abeta monomer folding and oligomerization, have revealed key structural features. These include turn formation in the Val24-Lys28 region of the unstructured Abeta monomer and interactions among the central hydrophobic cluster (Leu17-Ala21), N-terminus, and C-terminus. The four aims comprising this application seek to test mechanistic hypotheses emanating from these observations. Aim 1. To determine the mechanisms of turn formation in the Val24-Lys28 region of Abeta. a. To determine the role of hydrophobic interactions. b. To determine the role of electrostatic interactions. c. To determine the role of amino-acid turn propensity. Aim 2. To determine the mechanisms of intramolecular folding and early Abeta oligomerization. a. To determine the structural dynamics of central hydrophobic cluster (CHC)-C-terminus interactions. b. To determine the structural dynamics of CHC-N-terminus interactions. c. To determine the effects of alternative turn conformations on Abeta monomer structure and oligomerization. Aim 3. To use O?>N acyl migration chemistry to implement a new, quasisynchronous system for studies of Abeta42 folding and self-assembly. a. To synthesize 26-O-acyl-isoAbeta42 (26-AIAbeta42) and study the time-dependent changes in peptide secondary and quaternary structure following initiation of O?>N acyl migration. b. To use quasielastic light scattering spectroscopy to determine kinetic and thermodynamic parameters of Abeta42 self-assembly. c. To use ion mobility spectroscopy-mass spectrometry to monitor early oligomerization events in Abeta self-assembly. d. To synthesize and study the biophysical and biological behavior of Na-protected 26-AIAbeta42. Aim 4. To determine how structural features shown to be critical in controlling Abeta folding and oligomerization affect peptide neurotoxicity.

在阿尔茨海默氏病（AD）中，淀粉样β-蛋白质（Abeta）原纤维的进行性沉积，“淀粉样蛋白斑”，” 发生在大脑中。但是，在形成牙菌斑之前，神经元功能障碍可能发生。结构 - 神经毒性 研究表明，逐渐较小的有毒组件，包括原纤维， paranuclei和addls。在啮齿动物中，Abeta低聚物可以抑制长期增强（LTP），该模型的模型 学习和记忆。在AD患者中，ABETA低聚物的存在明显大于Angematched的水平 正常人。生物物理，细胞培养，动物和人类研究都支持 假设ABETA的寡化是AD发病机理中的关键事件。如果是这样，那么 治疗策略取决于阐明病理蛋白质折叠机制 寡聚和高阶组装。在我们的实验室继续努力以了解最早的 Abeta组件，Abeta单体折叠和低聚的步骤揭示了关键的结构特征。 其中包括在非结构化Abeta单体的Val24-Lys28区域中的转弯形成和相互作用 在中央疏水簇（LEU17-ALA21），N末端和C端。四个目标 包含此应用程序旨在测试这些观察结果产生的机械假设。 目的1。确定Abeta的Val24-Lys28区域中转弯形成的机理。 一个。确定疏水相互作用的作用。 b。确定静电相互作用的作用。 c。确定氨基酸转弯倾向的作用。 目标2。确定分子内折叠和早期Abeta低聚的机制。 一个。确定中央疏水簇（CHC）-C末端相互作用的结构动力学。 b。确定CHC-N-末端相互作用的结构动力学。 c。确定替代转弯构象对Abeta单体结构和低聚的影响。 目的3。使用O？> n酰基迁移化学来实施一个新的准同步系统 Abeta42折叠和自组装的研究。 一个。合成26-O-acyl-Isoabeta42（26-aiabeta42）并研究肽的时间依赖性变化 O？> n酰基迁移的次级和第四纪结构。 b。使用准灯光散射光谱来确定动力学和热力学参数 Abeta42自组装。 c。使用离子迁移率光谱质量光谱法监测Abeta自组装中的早期寡聚事件。 d。综合和研究Na保护26-Aiabeta42的生物物理和生物学行为。 目标4。确定结构特征如何在控制Abeta折叠和 寡聚影响肽神经毒性。