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 因此，保护​​生物免受代谢和新陈代谢的第一道防线 环境诱导的活性氧（ROS）。人线粒体 锰索（MNSOD）的表达被调制以防止基于ROS的损害， 促进氧化还原稳态，并保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 弄乱超氧化物。为此，需要所有原子的3D排列，大多数 重要的是质子的位置。我们最近与中子的技术进步 橡树岭国家实验室的晶体学克服了X-的局限性 射线晶体学 - 揭示高细节的质子位置，同时也允许 金属电子状态的控制。在这个研究项目中，MNSOD中子地图将 揭示质子继电器到活性位点金属和金属的质子化状态 结合配体。这项研究的科学假设是MNSOD转移质子 通过部分暴露氨基酸从一小部分水分子到 几乎完全埋葬了锰，以释放超氧化物对氢 通过环状金属氧化还原反应的过氧化物和分子氧。具体目的是 通过研究质子来表征MNSOD的电子耦合质子继电器 （1）降低和氧化锰的静息状态的环境 位点，（2）产品抑制Mn-过氧化物，（3）超氧化物结合 酶。将进行晶体的光谱法以帮助设计/理解 晶体学实验和关于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。最终的协议，方法和结构将具有特定的 结构生物学，抗氧化剂和金属酶学领域的人们的兴趣 一般来说，生物学家感兴趣。