Synthetic Models and Spectroscopy of Nonheme Diiron Enzymes

非血红素二铁酶的合成模型和光谱学

• 批准号: 7363716
• 负责人: LAWRENCE QUE
• 金额: $ 28.37万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7363716
• 关键词: Active Sites; Alkane 1-monooxygenase; Alkanes; Anabolism; Anti-HIV Therapy; Bacteria; Base Sequence; Binding; Biological; Biomimetics; Cell Proliferation; Ceruloplasmin; Class; Complex; Development; Diabetes Mellitus; Dioxygen; Electrochemistry; Electronics; Elongation Factor; Enzymes; Family; Fatty Acid Desaturases; Ferritin; Flavins; Goals; Hemerythrin; Histidine; Invertebrates; Iron; Kinetics; Lead; Ligands; Mammals; Mass Spectrum Analysis; Membrane; Metabolic; Metalloproteins; Methane hydroxylase; Methods; Mixed Function Oxygenases; Modeling; Oxidants; Oxidation-Reduction; Oxidoreductase; Oxygen; Peroxidase; Peroxidases; Peroxides; Pharmaceutical Preparations; Property; Proteins; Range; Research; Ribonucleotide Reductase; Sampling; Site; Spectrum Analysis; Structural Models; Structure; Techniques; Work; X-Ray Crystallography; adduct; carboxylate; complex IV; deoxyhypusine monooxygenase; desaturase; human disease; inositol oxygenase; insight; interest; novel; oxidation; programs; toluene 2-xylene monooxygenase; tumor

DESCRIPTION (provided by applicant): Project Summary. The goal of this proposal is to understand how dioxygen is activated by biological diiron centers in metabolically critical transformations. Nonheme diiron proteins and enzymes perform a variety of essential functions involving dioxygen, including dioxygen transport (hemerythrin), DMA biosynthesis (ribonucleotide reductase), iron storage (ferritin), and oxidations of organic substrates (methane monooxygenase, fatty acid desaturases, alkane and arene hydroxylases, myo-inositol oxygenase, deoxyhypusine hydroxylase). In general, dioxygen activation is proposed to entail a common mechanism involving diiron(lll)-peroxo intermediates and high-valent iron-oxo species derived therefrom. The project goal will be accomplished using a combination of biomimetic and spectroscopic approaches. Building on past accomplishments in modeling structural and spectroscopic properties of such sites, it is proposed to synthesize precursor complexes of tripodal ligands, to react them with O2 or peroxides, and to characterize the metastable intermediates derived therefrom. Of great interest are intermediates such as O2 adducts of diiron(ll) complexes (either iron(ll)iron(lll)-superoxo or diiron(lll)-peroxo species), and species with Fe(lll-)Fe(-IV) and Fe(-IV)Fe(-lV) oxidation states. These complexes will be characterized by X-ray crystallography whenever possible and by a variety of techniques such as NMR, EPR, UV-vis-NIR, Raman, Mossbauer, electrospray mass spectrometry, electrochemistry, and EXAFS. Both stopped-flow and conventional kinetic methods will be used to characterize their mechanisms of formation and decomposition. The oxidative reactivities of these transient complexes towards a range of substrates will be investigated and compared with those of enzyme active sites. Also to be synthesized are complexes that can serve as precedents for the novel oxygen activation mechanism recently proposed for myo-inositol oxygenase entailing an iron(ll)iron(lll) center that binds O2 and a diiron(lll)-superoxo species that acts as the initial oxidant. Parallel to these efforts, our spectroscopic expertise will be applied to elucidating the diiron site structures of methane monooxygenase intermediates and deoxyhypusine hydroxylase. Relevance. Nonheme diiron enzymes perform a variety of metabolically critical functions that require dioxygen activation. Understanding how these enzymes work can lead to the development of new drug strategies for treating some human diseases. For example, myo-inositol oxygenase may be connected to the many complications associated with diabetes mellitus, while deoxyhypusine hydroxylase is required for the formation of mature eukaryotic elongation factor 5a that is essential for cell proliferation and may thus serve as the target for anti-tumor or anti-HIV therapy.

描述（申请人提供）：项目摘要。该提案的目的是了解如何在代谢批判性转化中被生物二铁中心激活二氧化物。 Nonheme diiron proteins and enzymes perform a variety of essential functions involving dioxygen, including dioxygen transport (hemerythrin), DMA biosynthesis (ribonucleotide reductase), iron storage (ferritin), and oxidations of organic substrates (methane monooxygenase, fatty acid desaturases, alkane and arene hydroxylases, myo-inositol氧合酶，脱氧蛋白羟化酶）。通常，提出了二氧化激活，以需要一种涉及二龙（LLL） - 过氧中间体和从那里得出的高价值铁氧物种的共同机制。项目目标将使用仿生和光谱方法的组合来实现。基于对此类部位的结构和光谱特性进行建模的成就，它提议合成三座配体的前体配合物，以与O2或过氧化物反应，并表征其从中衍生得出的亚稳态中间体。引人注目的是中间体，例如二龙（LL）配合物的O2加合物（铁（LL）铁（LLL） - 苏植物或二烯（LLL） - 过氧物种），以及具有Fe（lll-）Fe（-IV）和Fe（-IV）和Fe（-iv）Fe（-iv）Fe（-iv）Fe（-lv）氧化态的物种。这些复合物将尽可能以X射线晶体学为特征，以及各种技术，例如NMR，EPR，UV-VIS-NIR，Raman，Mossbauer，Electrospray质谱，电化学和EXAFS。停止流量和常规动力学方法都将用于表征它们的形成和分解机制。这些瞬态复合物朝向一系列底物的氧化反应率将进行研究，并将其与酶活性位点的氧化反应能力进行比较。同样要合成的是复合物，可以作为最近提出的新型氧气激活机制的先例，该机制是针对结合O2和二烷（LLL）-superoxo物种的铁（LL）铁（LL）铁（LL）铁（LL）铁（LLL）中心的，该中心充当初始氧化剂。与这些努力平行，我们的光谱专业知识将用于阐明甲烷单加氧酶中间体和脱氧蛋白酶羟化酶的二烯位点结构。关联。非血红素二铁酶执行需要二氧化激活的各种代谢关键功能。了解这些酶的工作如何导致制定治疗某些人类疾病的新药物策略。例如，肌醇氧酶可能与糖尿病相关的许多并发症有关，而脱氧类蛋白羟化酶则需要形成成熟的真核延伸因子5a，这对于细胞增殖至关重要，因此可以作为抗肿瘤或抗抗抗血素或抗抗HIV治疗的靶标。