Endogenous protein engineering mechanismof oxidative stress in Alzheimer's disease

阿尔茨海默氏症是一种慢性神经退行性疾病，影响大量老龄人口。那里 目前还没有治愈这种疾病的方法，了解其病理机制可能是最有效的策略 找到解药活性氧（ROS）引起氧化应激，并在细胞凋亡中起重要作用。 阿尔茨海默病的发病机制。然而，ROS作用的确切机制尚不清楚。ROS 氧化DNA、蛋白质、脂质和小分子。羰基化是蛋白质氧化的一种模式， 发生在对铁催化的、过氧化氢（H2 O2）依赖的氨基酸侧氧化的响应中 店尽管羰基化蛋白通常被认为是由蛋白酶体消除的， 依赖性降解，我的实验室发现了蛋白质去羰基化机制， 所形成的羰基被酶促消除而蛋白质不被降解。主要氨基酸 对羰基化敏感的残基包括脯氨酸和精氨酸，它们都被氧化成 变成含有羰基的谷氨酸半醛。此外，谷氨酸的氧化 半醛产生谷氨酸。因此，我假设，通过ROS介导的 蛋白质结构内的谷氨酸半醛、脯氨酸、精氨酸和谷氨酸残基可以是 可以互换事实上，我们最近的质谱结果表明，脯氨酸45（一个保守的 过氧化物氧还蛋白6蛋白分子的催化序列内的残基）可以转化为 谷氨酸在人体细胞中，建立了一个革命性的概念，铁催化氧化eliminates 生物系统中蛋白质结构内的氨基酸转化。R 03项目的目标是 为氧化剂介导的氨基酸转化的发生提供证据， 氧化应激导致阿尔茨海默病的机制。本申请的目的是 通过追求两个具体目标来实现：1）鉴定脯氨酸45到谷氨酸的发生 从阿尔茨海默病患者获得的脑组织中过氧化物酶氧还蛋白6分子内的转化 2）确定脯氨酸45转化为谷氨酸对过氧化物氧还蛋白6活性的影响;和 3)探索Tau蛋白分子内的脯氨酸残基转化为谷氨酸的可能性 阿尔茨海默病患者大脑中的酸性物质。这项工作极具创新性，因为它将 解决了一个革命性的概念，即定点诱变/蛋白质工程样事件的发生 自然.结果将是有意义的，因为它们有望提供一种新的分子机制 ROS通过其引起神经损伤并帮助开发预防和/或治疗 老年痴呆症

Alzheimer's is a chronic neurodegenerative disease that affects a large number of aging populations. There is no cure for this disease and understanding the pathologic mechanism is likely the most effective strategy to find the cure. Reactive oxygen species (ROS) cause oxidative stress and play an important role in the pathogenesis of Alzheimer's disease. However, the exact mechanism of ROS action is unknown. ROS oxidize DNA, proteins, lipids and small molecules. Carbonylation is one mode of protein oxidation that occurs in response to iron-catalyzed, hydrogen peroxide (H2O2)-dependent oxidation of amino acid side chains. Although carbonylated proteins are generally thought to be eliminated by the proteasome- dependent degradation, my laboratory discovered the protein de-carbonylation mechanism, in which formed carbonyl groups are enzymatically eliminated without proteins being degraded. Major amino acid residues that are susceptible to carbonylation include proline and arginine, both of which get oxidized to become glutamic semialdehyde that contains a carbonyl group. Further, the oxidation of glutamic semialdehyde produces glutamic acid. Thus, I hypothesize that, through the ROS-mediated formation of glutamic semialdehyde, proline, arginine and glutamic acid residues within the protein structure may be interchangeable. In fact, our recent mass spectrometry results demonstrated that proline 45 (a conserved residue within the catalytic sequence) of the peroxiredoxin 6 protein molecule can be converted into glutamic acid in human cells, establishing a revolutionizing concept that iron-catalyzed oxidation elicits the amino acid conversion within the protein structure in the biological system. The objective of this R03 project is to provide evidence for the occurrence of oxidant-mediated amino acid conversion as a novel mechanism of oxidative stress causing Alzheimer's disease. The objective of this application will be accomplished by pursuing two specific aims: 1) Identify the occurrence of proline 45 to glutamic acid conversion within the peroxiredoxin 6 molecule in brain tissues obtained from patients with Alzheimer's disease; 2) Define effects of the proline 45 to glutamic acid conversion on the peroxiredoxin 6 activity; and 3) Explore the possibility that proline residues within the Tau protein molecule are converted into glutamic acid in the brain of Alzheimer's disease patients. The proposed work is highly innovative because it will address a revolutionizing concept that site-directed mutagenesis/protein engineering-like events occur naturally. Results will be significant because they are expected to provide a new molecular mechanism through which ROS cause neurological damage and help developing strategies to prevent and/or treat Alzheimer's disease.