Radical SAM Enzymes: Molecular Mechanisms of Radical Initiation

自由基 SAM 酶：自由基引发的分子机制

• 批准号: 10370355
• 负责人: Joan B Broderick
• 金额: $ 35.55万
• 依托单位: MONTANA STATE UNIVERSITY - BOZEMAN
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10370355
• 关键词: Antibiotics; Biological; Biology; Carbon; Chemicals; Complex; DNA Repair; Disease; Electron Nuclear Double Resonance; Electron Spin Resonance Spectroscopy; Enzymes; Freezing; Goals; Human; Infection; Iron; Life; Metals; Microbe; Molecular; Organometallic Chemistry; Pathway interactions; Pharmacologic Substance; Process; Property; Reaction; Research; Structure; Sulfur; Work; X-Ray Crystallography; beneficial microorganism; catalyst; chemical reaction; cobamamide; cofactor; computer studies; insight; member; novel; pathogenic microbe; photolysis

Radical SAM is one of the largest enzyme superfamilies known, with its members catalyzing a remarkable diversity of reactions in all domains of life. Radical SAM enzymes are involved in the synthesis of essential cofactors and antibiotics, repair of DNA damage, and the assembly of complex biological metal clusters, among many other reactions. The presence of radical SAM enzymes in humans as well as in both beneficial and pathogenic microbes lends high significance to understanding their fundamental properties and mechanisms. The proposed research will develop a critical understanding of radical SAM mechanisms, in particular the radical initiation process common to all enzymes in this large and diverse superfamily. Research efforts will focus on trapping radical intermediates using rapid freeze- quench, cryoreduction, annealing, and photolysis approaches. These intermediates will then be characterized by using spectroscopic approaches such as electron paramagnetic resonance and electron- nuclear double resonance, and structural approaches such as X-ray crystallography. Computational studies will provide insights into stability/reactivity and reaction pathways. Much of the work will build on the recent discovery of a novel organometallic intermediate containing a direct bond between an iron of the iron-sulfur cluster and a carbon of an adenosyl moiety, a structure reminiscent of coenzyme B12. The results will provide an understanding of this fundamental and ubiquitous reaction in biology, and its surprising involvement of organometallic chemistry.

Radical SAM 是已知最大的酶超家族之一，其成员催化 生活各个领域的反应具有显着的多样性。自由基 SAM 酶参与 必需辅因子和抗生素的合成、DNA损伤的修复以及复合物的组装 生物金属簇，以及许多其他反应。人体中存在自由基 SAM 酶 以及有益微生物和病原微生物对于了解它们的作用具有重要意义 基本性质和机制。拟议的研究将形成对以下问题的批判性理解 自由基 SAM 机制，特别是这个大分子中所有酶共有的自由基引发过程 和多样化的超家族。研究工作将集中于利用快速冷冻捕获自由基中间体 淬火、低温还原、退火和光解方法。这些中间体随后将被 其特点是使用光谱方法，如电子顺磁共振和电子 核双共振和结构方法，例如 X 射线晶体学。计算型 研究将提供对稳定性/反应性和反应途径的见解。大部分工作将建立 关于最近发现的一种新型有机金属中间体，其含有铁之间的直接键 铁硫簇和腺苷部分的碳，其结构让人想起辅酶 B12。 研究结果将提供对生物学中这种基本且普遍存在的反应及其作用的理解。 有机金属化学的令人惊讶的参与。