Photogeneration of High-Valent Diiron Enzyme Mimics

高价二铁酶模拟物的光生作用

• 批准号: 6626180
• 负责人: Thomas G. Gray
• 金额: $ 4.16万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-11 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6626180
• 关键词: X ray crystallography; atomic absorption spectrometry; biomimetics; biotechnology; catalyst; chemical synthesis; cofactor; electrochemistry; electron transport; emission spectrometry; enzyme substrate; iron metabolism; iron sulfur protein; mass spectrometry; methane monooxygenase; nuclear magnetic resonance spectroscopy; oxidation; photochemistry; postdoctoral investigator; ribonucleotide reductase; synthetic enzyme

DESCRIPTION: (provided by applicant) A novel, laser flash-quench approach to high oxidation state oxo-bridged diiron enzyme mimicry is described. Specifically, the enzymes soluble methane monooxygenase (MMO) and class I ribonucleotide reductase (RR) proceed through diiron(IV) (MMO) or iron(III)-iron(IV) (RR) intermediates at critical junctures in their catalytic cycles. Such unstably high oxidation states are difficult to achieve in model complexes. A brief review of relevant biochemistry is followed by the synthetic and photochemical strategy devised to generate diiron centers in the requisite oxidation states. An extensively characterized oxo-bondged diferric complex is tethered covalently, at both ends, to well-studied ruthenium or rhenium lumophores possessing long-lived triplet excited states. Electronic excitation of the photoactive part begins a redox cascade, where an external acceptor is reduced and one or both ferric sites are oxidized to iron(IV). The fate of the iron(IV) species can be monitored with time-resolved laser absorption spectroscopy. In additional experiments, enzyme substrates or substrate analogues are added, and their oxidation products, if any, are characterized. Control experiments are described to confirm that substrate reactivity indeed originates from iron(IV). The strategy, if successful, would allow a quantitative description of FeIV FeIV or FeIII FeIV -complex reactivity towards oxidizable substrates, with direct applicability to biochemical research in oxodiiron enzymes. The ideas within are applied to iron enzymes, but extend to other metals as well.

描述：（由申请人提供） 描述了高氧化态氧化二铁酶模仿。 具体而言，酶可溶性甲烷单加仑酶（MMO）和I类 核糖核苷酸还原酶（RR）通过二龙（IV）（MMO）或 铁（iii） - 铁（IV）（RR）在其催化中的临界点处的中间体 周期。在模型中难以实现这种不及时的高氧化态 复合物。对相关生物化学的简要审查，然后是合成的 并设计为在必要的情况下生成二龙中心的光化学策略 氧化状态。广泛表征的氧粘结差异复合物是 在两端共价束缚，以进行精心研究 具有长寿命的三胞胎激发态的分流器。电子激发 光活性部分的开始是一个氧化还原级联，外部受体是 减少和一个或两个铁位被氧化为铁（IV）。命运 铁（IV）物种可以通过时间分辨激光吸收来监测 光谱法。在其他实验中，酶底物或底物 添加了类似物，并表征其氧化产物（如果有）。 描述了对照实验以确认底物反应性确实 起源于铁（IV）。如果成功的话，该策略将允许 FEIV FEIV或FEIII FEIV -COMPERX反应性的定量描述 可氧化的底物，直接适用于生化研究 氧化酶。内部的想法应用于铁酶，但扩展到 其他金属也是如此。