Folding and Aggregation Mechanisms of Human Cu,Zn Superoxide Dismutase

人铜、锌超氧化物歧化酶的折叠和聚集机制

• 批准号: 8066938
• 负责人: C Robert Matthews
• 金额: $ 33.22万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-01 至 2014-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8066938
• 关键词: Acquired Immunodeficiency Syndrome; Amides; Amino Acids; Amyotrophic Lateral Sclerosis; Cells; Cuprozinc Superoxide Dismutase; Cysteine; Dehydration; Development; Diffusion; Dimerization; Disease; Equilibrium; Event; Fluorescence; Fluorescence Resonance Energy Transfer; Fluorescence Spectroscopy; Free Energy; Future; Goals; Grant; HIV-1; Height; Human; Hydration status; Hydrogen; In Vitro; Individual; Induced Mutation; Kinetics; Label; Mass Spectrum Analysis; Measures; Modeling; Molecular; Monitor; Motor Neurons; Mutation; NMR Spectroscopy; Neurodegenerative Disorders; Optical Methods; Oxidative Phosphorylation; Oxygen; Pathology; Pattern; Peptide Hydrolases; Peptides; Population; Positioning Attribute; Property; Proteins; Reaction; Resistance; Resistance development; Role; Shapes; Side; Solvents; Source; Spectrum Analysis; Staging; Structure; Superoxides; Surface; System; Techniques; Temperature; Testing; Thermodynamics; Time; Urea; Variant; Water; base; chromophore; comparative; fluorophore; in vivo; inhibitor/antagonist; insight; monomer; pandemic disease; public health relevance; research study; technology development

DESCRIPTION (provided by applicant): Human Cu,Zn superoxide dismutase (SOD1) converts superoxide, a toxic byproduct of oxidative phosphorylation, into water and oxygen in all respiring cells. Tragically, mutations at dozens of positions in SOD1 cause amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease. A prevailing hypothesis for the molecular mechanism of the disease involves the aggregation of marginally-soluble forms of SOD1 whose populations are increased by the ALS-inducing mutations. Biophysical analysis of the folding mechanism of this dimeric ¿-barrel protein and quantitative assessment of the perturbations in the populations of monomeric forms induced by mutations, performed during the previous grant period, support this hypothesis. The overall goals of the present proposal are (1) to examine the structural, thermodynamic and kinetic properties of the rate-limiting monomer folding reaction in ALS-variants of SOD1 and (2) to develop and apply fluorescence-based optical methods to monitor directly the subsequent diffusion-limited subunit association reaction and the formation of oligomers during the early stages of the aggregation reaction. A combined denaturant and temperature analysis of the kinetic folding reaction will provide insights into the thermodynamic properties of the transition state ensemble (TSE) controlling the formation of the folded monomeric state. A complementary mutational analysis will highlight the side chains involved in defining the TSE and test the role of hydration in determining the barrier for this extraordinarily slow reaction. Small angle x-ray scattering experiments will probe the size and shape of monomeric ALS variants of SOD1. The resistance of main chain amide hydrogens to exchange with solvent will be monitored by mass spectrometry and NMR spectroscopy to probe for persistent secondary structure in partially-folded states of SOD1 and several ALS variants. The results will be compared with the protection patterns observed in aggregates of the ALS variants. Forster resonance energy transfer and fluorescence correlation spectroscopy will be used to monitor the subunit association reaction and the early stages of the aggregation reaction for several ALS variants labeled with extrinsic chromophores. The results will provide a quantitative framework for describing the effects of ALS-inducing mutations on SOD1 and insights into the mechanism by which they enhance its propensity to aggregate. PUBLIC HEALTH RELEVANCE: Although inheritable mutations in SOD1 are responsible for only a small fraction of ALS cases, a detailed analysis of the mechanisms by which mutations in SOD1 enhance its aggregation propensity may provide a paradigm for other forms of ALS and other neurodegenerative diseases. The development and application of fluorescence correlation spectroscopy techniques to in vitro SOD1 folding and aggregation will enhance the understanding of the molecular basis of ALS and enable future applications to in vivo studies in cell-based systems.

描述（由适用提供）：人Cu，Zn超氧化物歧化酶（SOD1）将超氧化物（氧化物磷酸化的有毒副产品）转化为所有呼吸细胞中的水和氧气。可悲的是，SOD1中数十个位置的突变会导致肌萎缩性侧索硬化症（ALS），一种致命的神经退行性疾病。疾病分子机制的普遍假设涉及SOD1的边缘溶解形式的聚集，其人群通过ALS诱导的突变增加了。该二聚体的折叠机理的生物物理分析 - 桶蛋白和对在上一个赠款期间进行的突变诱导的单体形式种群中扰动的定量评估，支持此假设。本建议的总体目标是（1）检查SOD1和（2）中限制速率单体折叠反应的结构，热力学和动力学特性，以开发和应用基于荧光的光学方法，以直接监测随后的扩散限制的亚基缔合反应和在早期阶段的形成，以直接监测含有型的扩散的扩散限制性限制性限制性限制性。动力学折叠反应的结合变性剂和温度分析将为控制折叠单体状态的形成的过渡状态合奏（TSE）的热力学特性提供见解。完整的突变分析将突出涉及定义TSE的侧链，并测试水合在确定这种非常缓慢反应的屏障中的作用。小角度X射线散射实验将探测SOD1单体ALS变体的大小和形状。主链酰胺氢与溶剂交换的电阻将通过质谱和NMR光谱法监测，以探测SOD1和几种ALS变体的部分折叠状态中持续的二级结构。结果将与在ALS变体的聚集体中观察到的保护模式进行比较。 Forster共振能量转移和荧光相关光谱将用于监测几种标记为外部发色团标记的ALS变体的亚基关联反应和聚集反应的早期阶段。结果将提供一个定量框架，以描述ALS诱导的突变对SOD1的影响以及对它们增强其聚集承诺的机制的见解。 公共卫生相关性：尽管SOD1中的遗传突变仅负责ALS病例的一小部分，但对SOD1中突变增强其聚集承诺的机制的详细分析可能会为其他形式的ALS和其他神经退行性疾病提供范式。荧光相关光谱技术在体外SOD1折叠和聚集中的开发和应用将增强对ALS分子基础的理解，并使未来在基于细胞的系统中的体内研究对未来的应用进行应用。