Deciphering the Enzymatic Mechanism of Superoxide Dismutase

破译超氧化物歧化酶的酶促机制

• 批准号: 10418479
• 负责人: Gloria Borgstahl
• 金额: $ 43.14万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10418479
• 关键词: 3-Dimensional; Active Sites; Amino Acids; Antioxidants; Binding; Biological Process; Biology; Bypass; Cardiovascular system; Cells; Charge; Complex; Coupled; Coupling; Crystallization; Crystallography; Data; Data Collection; Dioxygen; Disease; Electron Transport; Electrons; Electrostatics; Environment; Enzymatic Biochemistry; Enzymes; Functional disorder; Future; Goals; Homeostasis; Human; Hydrogen; Hydrogen Peroxide; Investigation; Laboratories; Life; Ligand Binding; Ligands; Malignant Neoplasms; Manganese; Maps; Measures; Metabolic; Metals; Methods; Mitochondria; Mitochondrial Matrix; Modeling; Molecular; Nature; Neurodegenerative Disorders; Neutron Diffraction; Neutrons; Organism; Oxidation-Reduction; Oxidative Stress; Oxides; Oxidoreductase; Oxygen; Pathology; Periodicity; Positioning Attribute; Proteins; Protocols documentation; Protons; Reaction; Reactive Oxygen Species; Research; Research Project Grants; Rest; Role; SOD2 gene; Signal Transduction; Solvents; Spectrum Analysis; Structure; Superoxide Dismutase; Superoxides; Surface; System; Testing; Therapeutic; Therapeutic Intervention; Time; Variant; Water; X-Ray Crystallography; base; computational chemistry; design; experimental study; improved; interest; ionization; manganese oxide; metalloenzyme; novel strategies; prevent; protonation; reaction rate; structural biology; tool; working group

Abstract Superoxide dismutases (SODs) are the major regulators of oxidative stress and therefore the first line of defense to protect organisms against metabolic- and environmentally-induced reactive oxygen species (ROS). Human mitochondrial manganese SOD (MnSOD) expression is modulated to prevent ROS-based damage, promote redox homeostasis, and maintain proper cell signaling. Our research goal is to understand the molecular basis of how MnSOD uses coupled proton-electron transfers to dismute superoxide. For this, the 3D arrangement of all atoms is needed, most importantly the position of protons. Our recent technical advancements with neutron crystallography at Oak Ridge National Laboratory have overcome the limitations of X- ray crystallography – revealing proton positions with high detail while also allowing control of the metal electronic state. In this research project, MnSOD neutron maps will reveal the proton relays to the active site metal and the protonation states of metal- bound ligands. The scientific hypothesis for this study is that MnSOD transfers protons from a small group of water molecules via partially solvent-exposed amino acids to the nearly completely buried manganese for the dismutation of superoxide to hydrogen peroxide and molecular oxygen via cyclic metal redox reactions. The specific aims are to characterize the electron-coupled proton relays of MnSOD by investigating the proton environment of (1) the resting states of the reduced and oxidized manganese active sites, (2) the product inhibited Mn-peroxo complex, and (3) the superoxide bound enzyme. Spectroscopy on crystals will be performed to help design/understand crystallographic experiments, and computational chemistry studies on neutron derived all-atom structures will help tie the results together and test our interpretations about the enzymatic activity. The resulting protocols, methods, and structures will be of specific interest to those in the fields of structural biology, antioxidants, and metallo-enzymology and of interest to biologists in general.

抽象的 超氧化物歧化酶（SOD）是氧化应激和氧化应激的主要调节因子 因此，保护​​生物体免受代谢和代谢影响的第一道防线 环境诱导的活性氧（ROS）。人类线粒体 调节锰 SOD (MnSOD) 表达以防止基于 ROS 的损伤， 促进氧化还原稳态，维持适当的细胞信号传导。我们的研究目标是 了解 MnSOD 如何使用耦合质子电子转移的分子基础 使超氧化物歧化。为此，需要所有原子的 3D 排列，大多数 重要的是质子的位置。我们最近在中子方面的技术进步 橡树岭国家实验室的晶体学克服了 X- 射线晶体学 – 以高细节揭示质子位置，同时还允许 金属电子态的控制。在这个研究项目中，MnSOD 中子图将 揭示质子与活性位点金属的中继以及金属的质子化状态 结合配体。本研究的科学假设是 MnSOD 传输质子 从一小群水分子通过部分溶剂暴露的氨基酸到 几乎完全埋藏的锰用于将超氧化物歧化为氢气 通过循环金属氧化还原反应产生过氧化物和分子氧。具体目标是 通过研究质子来表征 MnSOD 的电子耦合质子继电器 (1)还原态和氧化态锰活性的环境 位点，(2) 产品抑制锰-过氧复合物，(3) 超氧化物结合 酶。将对晶体进行光谱分析以帮助设计/理解 晶体学实验和中子衍生的计算化学研究 全原子结构将有助于将结果联系在一起并测试我们对 酶活性。由此产生的协议、方法和结构将具有特定的 对结构生物学、抗氧化剂和金属酶学领域感兴趣的人 并引起了一般生物学家的兴趣。