Exploration of the chemical and mechanistic diversity of mixed-valent iron oxygenases and oxidases

混合价铁加氧酶和氧化酶的化学和机制多样性的探索

• 批准号: 2108583
• 负责人: Carsten Krebs
• 金额: $ 61.89万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2108583&HistoricalAwards=false
• 关键词: Exploration; chemical; mechanistic; diversity; mixed

With the support of the Chemistry of Life Sciences Program in the Division of Chemistry, Professors Carsten Krebs, J. Martin Bollinger, Jr., and Alexey Silakov at Penn State University will use analytical, kinetic, and spectroscopic methods to understand how a new functional class of iron enzymes use molecular oxygen (O2) to carry out complex biochemical transformations in nutrient-acquisition and biosynthetic pathways in bacteria. Such enzymes catalyze reactions that generally exceed the current capabilities of synthetic chemists and could be used directly or purposefully evolved to make high-value chemicals including drugs. Most of these enzymes have cofactors consisting of one or two iron ions in the reduced iron(II) form. In 2006 the investigators identified a new functional class of enzymes that use mixed-valent diiron cofactors, i.e. cofactors that contain one reduced iron(II) and one oxidized iron(III) ion to catalyze complex four-electron oxidations of diverse substrates. How this first subfamily of mixed-valent diiron enzymes catalyze their reactions is only partly understood. The research will seek to reveal key principles of the catalytic cycles of the enzymes by direct structural interrogation of reactive intermediates. Together with collaborators, the scientists will also study multinuclear iron enzymes that have an architecture called "TIM-barrel." These enzymes catalyze remarkable rearrangement of peptides to make copper chaperones and antibiotics and also use mixed-valent di- or tri-iron cofactors. The project will be one of several used to reveal general principles and approaches in metallobiochemistry within the Penn State group's biennial bioinorganic-chemistry training program, which trains undergraduate and Ph.D. students from around the world via recorded and publicly available lectures and hands-on practical training sessions on more than 20 techniques central for bioinorganic chemistry and related research areas.In the first aim of the project, the nature of the related diiron(III)-superoxide intermediates that abstract hydrogen atoms to initiate oxidative carbon-carbon and carbon-phosphorus bond cleavage reactions in three different enzymes will be probed by isotope-labeling and pulse electron paramagnetic resonance (EPR) methods. Analytical methods to trace the path of the oxygen atoms from O2 and H2O into the products will help explain puzzling preliminary observations and clarify their mechanisms. In the second aim, the nature of the cofactors in the new heterodimeric TIM-barrel, mixed-valent iron enzymes will be defined by Mössbauer and EPR spectroscopies. The crucial questions are whether there are two or three iron ions in the cofactors and whether they form superoxo-Fe2-3 complexes that abstract hydrogen atoms to initiate the complex rearrangements of cysteine-containing peptides that make the copper chaperones known as methanobactins and the antibiotic L-thiaglutamate. The understanding that will emerge from these studies will inform discovery and directed evolution of new biocatalytic reactions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学化学科学计划的支持下，宾夕法尼亚州立大学的Carsten Krebs，J。MartinBollinger，J。Martin Bollinger和Alexey Silacov将使用分析性，动力学和光谱方法来了解新功能性的铁酶（O2）的新功能性化合物 - 细菌中的生物合成途径。酶催化通常超过合成化学家当前功能的反应，可以直接或有目的地进化为制造包括药物在内的高价值化学物质。这些酶中的大多数具有由铁（II）形式的一个或两个铁离子组成的辅因子。 2006年，研究人员确定了一种新的功能性类别的酶，该酶使用混合价值的Diron辅助因子，即包含一种还原铁（II）和一种氧化物铁（III）离子的辅因子来催化潜水员底物的复杂四电子氧化物。这种混合价值diron酶的第一个亚家族如何催化其反应，只能部分理解。该研究将寻求通过直接对反应性中间体的结构审查来揭示酶催化循环的关键原理。科学家还将与合作者一起研究具有称为“ Tim-Barrel”的建筑的多核铁酶。这些酶催化了宠物的显着重排，以制造铜链条和抗生素，并使用混合价值的二型或三铁辅因子。该项目将是宾夕法尼亚州立大学两年一的生物学化学化学培训计划中揭示金属生物化学的一般原则和方法的几个项目之一，该计划培训本科生和博士学位。来自世界各地的学生通过记录和公开可用的讲座和对20多种技术的实践培训课程，用于生物无机化学和相关研究领域。通过同位素标记和脉冲电子顺磁共振（EPR）方法。将氧原子从O2和H2O追踪到产品的路径的分析方法将有助于解释难题的初步观察并阐明其机制。在第二个目标中，新的异二聚体Tim-Barrel中辅因子的性质，混合价铁酶将由Mössbauer和EPR光谱镜定义。至关重要的问题是，辅因子中是否有两个或三个铁离子，以及它们是否形成超氧基-FE2-3络合物，它们抽象氢原子以启动含有半胱氨酸的含有半胱氨酸的肽的复杂重排，使铜链酮使铜链酮和抗生素L-噻思丁氨酸酯抗生素被称为甲烷酸酯和抗生素。从这些研究中得出的理解将为发现新生物催化反应的发现和指示进化。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，被视为通过评估来获得珍贵的支持。