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（由申请人提供）：项目概述。本提案的目的是了解在代谢关键转化中生物双铁中心如何激活双氧。非血红素二铁蛋白和酶具有多种与双氧有关的基本功能，包括双氧运输（甲氰脲）、DMA生物合成（核糖核苷酸还原酶）、铁储存（铁蛋白）和有机底物的氧化（甲烷单加氧酶、脂肪酸去饱和酶、烷烃和芳烃羟化酶、肌醇加氧酶、脱氧hypusine羟化酶）。一般来说，双氧活化被认为是一个共同的机制，涉及双铁(ll)-过氧中间体和由此衍生的高价氧化铁。该项目的目标将通过结合仿生学和光谱方法来实现。基于过去在模拟这些位点的结构和光谱特性方面的成就，我们建议合成三足配体的前体配合物，使它们与O2或过氧化物反应，并表征由此产生的亚稳中间体。人们对二铁（ll）配合物的O2加合物(无论是铁（ll）铁（ll) -超氧或二铁(ll) -过氧）以及具有Fe(ll -)Fe（- iv）和Fe(- iv)Fe（- lv）氧化态的中间体非常感兴趣。这些配合物将尽可能通过x射线晶体学和各种技术进行表征，如NMR， EPR, UV-vis-NIR，拉曼，穆斯堡尔，电喷雾质谱，电化学和EXAFS。堵流和常规动力学方法都将用于表征它们的形成和分解机制。这些瞬态复合物对一系列底物的氧化反应性将被研究，并与酶活性位点的氧化反应性进行比较。还将合成配合物，这些配合物可以作为最近提出的肌醇加氧酶的新氧激活机制的先例，该机制涉及结合O2的铁（ll）铁（ll）中心和作为初始氧化剂的二铁(ll) -超氧物质。与这些努力平行，我们的光谱专业知识将应用于阐明甲烷单加氧酶中间体和脱氧hypusine羟化酶的二铁位点结构。的相关性。非血红素二铁酶执行各种代谢关键功能，需要双氧激活。了解这些酶的工作原理有助于开发治疗某些人类疾病的新药物策略。例如，肌醇加氧酶可能与糖尿病相关的许多并发症有关，而脱氧hypusine羟化酶是形成成熟的真核延伸因子5a所必需的，而真核延伸因子5a是细胞增殖所必需的，因此可能作为抗肿瘤或抗hiv治疗的靶标。