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: 10592256
• 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/10592256
• 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.

激进的SAM是已知的最大酶超家族之一，其成员催化A 生命的所有领域中反应的显着多样性。激进的SAM酶参与 必需辅助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。人类中的激进SAM酶的存在 以及在有益和致病性微生物中都具有很高的意义 基本特性和机制。拟议的研究将对 激进的SAM机制，尤其是在这个大型酶中共有的激进启动过程 和多样化的超家族。研究工作将着重于使用快速冻结 - 淬灭，冷冻，退火和光解方法。这些中间体将是 通过使用光谱方法（例如电子顺磁共振和电子）来表征 核双共振和X射线晶体学等结构方法。计算 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 最近发现了一个新型有机金属中间体，该中间体包含铁之间的直接键 铁硫簇和腺基部分的碳，一种让人联想的辅酶B12的结构。 结果将提供对生物学中这种基本和普遍反应的理解， 令人惊讶的是有机金属化学的参与。