Synthesis and Spectroscopy of Ferric Superoxo Models for Non-Heme Enzyme Intermediates

非血红素酶中间体三价铁超氧模型的合成和光谱分析

• 批准号: 8834013
• 负责人: Caleb James Allpress
• 金额: $ 5.41万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-16 至 2017-02-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8834013
• 关键词: Acidity; Acids; Active Sites; Anabolism; Antibiotics; Binding; Biochemical Reaction; Ceruloplasmin; Characteristics; Chemistry; DNA; Deoxyribonucleotides; Electron Spin Resonance Spectroscopy; Electronics; Enzymes; Ferritin; Frequencies; Generations; Goals; Heme; Heme Iron; Hydrogen Bonding; Investigation; Iron; Ligands; Methodology; Methods; Modeling; Modification; Mono-S; Mononuclear; Mossbauer Spectroscopy; Nuclear; Outcomes Research; Oxygen; Oxygenases; Pathway interactions; Penicillins; Process; Property; Raman Spectrum Analysis; Reaction; Reactive Oxygen Species; Reporting; Research; Role; Series; Site; Spectrum Analysis; Stretching; Structure; Superoxides; System; Techniques; Temperature; Viscosity; X-Ray Crystallography; alkalinity; clorobiocin; cold temperature; design; flexibility; oxidation; prevent; public health relevance

 DESCRIPTION (provided by applicant): Non-heme, iron-containing oxygenases are involved in various biomedically important processes, including the biosynthesis of antibiotics (including chlorobiocin and penicillin), the generation of deoxyribonucleotides (key building blocks of DNA), and the storage of iron to prevent damaging Fenton-type chemistry (via the ferroxidase site of ferritin). Understanding how oxygenases use activated iron-oxygen species to carry out these transformations is of paramount importance. Despite the wealth of studies on the role of iron-oxo and iron-peroxo species, there is a paucity of spectroscopically accessible iron-superoxo compounds known. This is surprising given that iron-superoxo species are proposed as early intermediates in the catalytic cycles of almost every non-heme iron-containing oxygenase enzyme. The goal of this proposal is to generate spectroscopically tractable Fe(III)-superoxo species of relevance to non-heme iron-containing oxygenases. This will be accomplished by developing a synthetic methodology for mononuclear non-heme Fe(III)-superoxo species. We hypothesize that by appropriate combination of reaction conditions and ligand design features (including ligand basicity, steric bulk and hydrogen bond donor ability) we will be able to generate the first synthetic mononuclear non-heme Fe(III)-superoxo species. We will also apply similar design principles to the generation of Fe(III)-superoxo compounds from dinuclear precursors containing a Fe(II) center. The synthetic Fe(III)-superoxo compounds will be comprehensively characterized by a variety of spectroscopic methods including UV-vis, XAS, resonance Raman, EPR, and Mössbauer spectroscopy. This will allow the establishment of an understanding of the relationship between primary- and secondary- coordination sphere features of the compounds to the structural and electronic features of iron-superoxo species. To date no non-heme iron-superoxo compound has been fully characterized by a combination of Raman, EPR and Mössbauer spectroscopy, and this is a significant gap in understanding for the field. In fact, only a single such superoxo compound has been characterized by resonance Raman, and the O-O stretching frequency of 1310 cm-1 is anomalously high compared to other known superoxide compounds (1043-1207 cm-1). The reactivity of the synthesized Fe(III)-superoxo compounds will also be explored in order to establish a reactivity relationship to electronic and structural parameters. Overall, this research has the potential to be transformative to understanding the role of superoxide intermediates in the field of non-heme iron-containing oxygenases.

 描述（由申请人提供）：非血红素、含铁加氧酶参与各种重要的生物医学过程，包括抗生素（包括氯生菌素和青霉素）的生物合成、脱氧核糖核苷酸（DNA 的关键组成部分）的产生以及储存铁以防止破坏芬顿型化学（通过铁蛋白的亚铁氧化酶位点）了解加氧酶如何使用活化的铁氧物质。尽管对铁-氧和铁-过氧化合物的作用进行了大量研究，但已知的可光谱分析的铁-超氧化合物却很少，考虑到铁-超氧化合物，这是令人惊讶的。被提议作为几乎所有非血红素含铁加氧酶催化循环的早期中间体。该提议的目标是产生光谱上可处理的相关 Fe(III)-超氧物种。这将通过开发单核非血红素 Fe(III)-超氧物种的合成方法来实现，我们通过反应条件和配体设计特征（包括配体碱性、空间结构）的适当组合来实现这一点。本体和氢键供体能力），我们将能够生成第一个合成的单核非血红素 Fe(III)-超氧化合物。我们还将应用类似的设计原理来生成 Fe(III)-超氧化合物。含有 Fe(II) 中心的双核前体将通过多种光谱方法进行全面表征，包括 UV-vis、XAS、共振拉曼、EPR 和穆斯堡尔光谱。理解化合物的初级和次级配位层特征与铁超氧物种的结构和电子特征之间的关系迄今为止，还没有完全表征非血红素铁超氧化合物。结合拉曼、EPR 和穆斯堡尔光谱，这是对该领域理解的重大差距。事实上，只有一种此类超氧化合物通过共振拉曼进行了表征，并且 O-O 伸缩频率为 1310 cm-1。与其他已知的超氧化物化合物 (1043-1207 cm-1) 相比，合成的 Fe(III)-超氧化合物的反应性也异常高。总体而言，这项研究有可能对理解超氧化物中间体在非血红素含铁加氧酶领域的作用产生革命性的影响。