Co(II) Radical Pair Dynamics in B12 Enzyme Catalysis

B12 酶催化中的 Co(II) 自由基对动力学

• 批准号: 8918207
• 负责人: KURT WARNCKE
• 金额: $ 9.14万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-15 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8918207
• 关键词: Acceleration; Address; Biochemical; Carbon; Catalysis; Chemicals; Cobalt; Computer software; Coupled; Coupling; DNA Sequence Rearrangement; Development; Electron Spin Resonance Spectroscopy; Entropy; Environment; Enzymes; Equilibrium; Ethanolamine Ammonia-Lyase; Free Energy; Free Radicals; Freezing; Funding; Generations; Glass; Goals; Health; Human; Ice; Individual; Kinetics; Measures; Mediating; Metals; Methods; Modeling; Molecular; Molecular Structure; Motion; Optics; Outcome; Outcomes Research; Physiologic pulse; Process; Property; Protein Dynamics; Proteins; Reaction; Relaxation; Relaxation Techniques; Research; Resolution; Role; Salmonella typhimurium; Sampling; Solutions; Solvents; Structure; Sucrose; System; Techniques; Temperature; Time; Variant; Water; antimicrobial; aqueous; base; biophysical techniques; catalyst; cobamamide; cold temperature; covalent bond; design; enzyme model; inhibitor/antagonist; insight; interstitial; molecular dynamics; photolysis; programs; protein structure; research study; theories; tool

DESCRIPTION (provided by applicant): The long-term goal of the proposed research is to elucidate fundamental molecular principles that govern catalysis in enzymes, in the context of metal-radical pair generation and coupled radical-mediated reactions. This goal will be enacted through a comprehensive program of biochemical and physical studies of the coenzyme B12 (adenosylcobalamin) - dependent enzyme, ethanolamine ammonia-lyase, from Salmonella typhimurium. We have developed new methods, software and hardware for pulsed-electron paramagnetic resonance (EPR) spectroscopy. In conjunction with biochemical techniques, we have developed low-temperature systems and time- resolved EPR approaches that enable pioneering experimental efforts that address, directly, covalent bond- breaking/bond-making reactions in ethanolamine ammonia-lyase at single-step resolution. The general aims are to define the free energy landscape that guides the reactions, identify the origins and characterize the roles of the protein and coupled solvent fluctuations that propel the system over this landscape, and resolve the Angstrom-scale molecular structures that frame the free energy landscape. The projects develop a proposed "configurational catalysis" model for enzyme catalysis, and seek to establish the radical rearrangement as a paradigm for defining landscape and protein-solvent motional contributions to chemical steps in enzyme reactions. Contributions of solvent structure and dynamics to the enzyme reactions are also addressed by a suite of EPR spectroscopic and relaxation techniques. The outcomes of the research will impact molecular approaches in biomedicine and human health, including anti- microbial therapies, rational design of catalysts, inhibitors, and bio-nanocompartments, and control of free radical reactions.

描述（由申请人提供）：拟议研究的长期目标是阐明在金属激进对生成和耦合自由基介导的反应的背景下，在酶中控制催化的基本分子原理。该目标将通过辅助酶B12（腺苷核素）的生化和物理研究的综合计划 - 依赖性酶，乙醇胺氨 - ly酶，来自鼠伤寒沙门氏菌。我们开发了用于脉冲电子顺磁共振（EPR）光谱的新方法，软件和硬件。结合生化技术，我们开发了低温系统和时间解析的EPR方法，使得在单步分辨率下直接解决乙醇胺氨 - 溶解酶的共价断裂/结合反应的开创性实验努力。一般目的是定义指导反应，确定起源并表征蛋白质和耦合溶剂波动的作用的自由能景观，这些波动可以推动系统在该景观上推动系统，并解决构成自由能景观的Angstrom量表分子结构。这些项目开发了一种用于酶催化的“构型催化”模型，并试图建立根治性重排作为定义景观和蛋白质溶解的运动对酶反应化学步骤的贡献的范式。溶剂结构和动力学对酶反应的贡献也由EPR光谱和松弛技术套件来解决。这项研究的结果将影响生物医学和人类健康的分子方法，包括抗微生物疗法，催化剂的合理设计，抑制剂和生物 - 纳米校区以及对自由基反应的控制。