Heme-dependent chemistry in tyrosine oxidation: Diversity Supplement on 5R01GM108988-08 for supporting Samuel Montoya

酪氨酸氧化中的血红素依赖性化学：5R01GM108988-08 上的多样性补充，用于支持 Samuel Montoya

• 批准号: 10167195
• 负责人: Aimin Liu
• 金额: $ 6.11万
• 依托单位: UNIVERSITY OF TEXAS SAN ANTONIO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10167195
• 关键词: Active Sites; Amino Acid Sequence; Anabolism; Antibiotics; Bacterial Infections; Biological; Carbon; Catalysis; Cations; Characteristics; Charge; Chemicals; Chemistry; Coupled; Coupling; Crystallization; Cysteine; Cytochrome P450; Cytochrome a; Data; Dioxygenases; Distal; Dopa; Drug Design; Electrons; Environment; Enzymes; Funding; Goals; Grant; Health; Heme; Heme Iron; Histidine; Human; Hydrogen Bonding; Hydrogen Peroxide; Hydroxylation; Investigation; Iron; Knowledge; Laboratories; Lead; Levodopa; Ligands; Malignant Neoplasms; Mediating; Molecular; Mononuclear; Mycobacterium tuberculosis; Natural Products; Oxidants; Oxides; Oxygenases; Parents; Pathway interactions; Peptides; Peroxidases; Pharmaceutical Preparations; Phenols; Play; Porphyrins; Positioning Attribute; Process; Production; Prosthesis; Protein Engineering; Proteins; Protons; Reaction; Research Project Grants; Role; Scheme; Structure; Structure-Activity Relationship; System; Testing; Tryptophan; Tuberculosis; Tyrosine; Tyrosine 3-Monooxygenase; antimicrobial drug; antineoplastic antibiotics; antitumor agent; base; c new; cofactor; design; drug development; drug discovery; enzyme activity; enzyme mechanism; heme a; insight; member; metalloenzyme; novel; novel therapeutics; oxidation; pathogen; pathogenic bacteria; small molecule

Abstract of the Parent Research Project One of the hallmarks of heme iron-dependent enzymes is the wide array of oxidation reactions that it can catalyze with its high-valent iron-oxo species. However, one conundrum is that each protein, in general, promotes only a specific type of reaction. How the reaction type is determined after the formation of the critical oxidant remains an open question whose answers have implications for the fundamental understanding of enzyme catalysis as well as de novo enzyme design and protein engineering. Because tyrosine is an essential building block of natural products, this project focuses on a mechanistic characterization of three heme-dependent tyrosine-oxidizing enzymes. Each of these enzymes employs a mononuclear heme cofactor to oxidize its tyrosine-based substrate. Intriguingly, a cytochrome P450 protein, CYP121 from Mycobacterium tuberculosis, catalyzes an unusual oxidative carbon-carbon cross- coupling reaction instead of a more common hydroxylation reaction. We found that SfmD is a new member of the tryptophan dioxygenase superfamily that promotes a regioselective monooxygenation on a methylated tyrosine substrate. The peroxidase LmbB2 performs a peroxygenase-type of reaction with an axial ligand of histidine instead of cysteine. These enzymes not only catalyze tyrosine-based oxidation reactions, but they are also related to antimicrobial drug development. Given the similarities of the heme- based oxidant and the structure of the substrates, an inevitable question arises and will be answered by this study regarding the governing factors that determine the catalytic activity of these enzymes. In Aim #1, we will identify the mechanistic and structural characteristics of CYP121. Using a battery of spectroscopic and structural approaches coupled with synthetic probes, we will unveil a novel carbon- carbon coupling mechanism mediated by the P450 enzyme. In Aim #2, we will characterize the structure and mechanism of SfmD with an emphasis on how the substrate is positioned to the iron-bound oxidant and the capture of catalytic intermediates. We have already identified that this protein is a novel heme- based oxygenase. Aim #3 will focus on studying the peroxidase reaction catalyzed by LmbB2 that is responsible for L-3,4-dihydroxyphenylalanine (L-DOPA) formation through L-tyrosine hydroxylation. We will utilize small-molecule probes to interrogate mechanistic pathways. The in-depth analysis of these three related catalytic systems will test our hypothesis regarding how the heme-bound oxidant is generated and directed to the aromatic substrates, unravel the structure-function relationships of the heme enzymes of seemingly unrelated superfamilies at a higher level, and develop underlying mechanisms further aiding rational drug design and discovery processes.

家长研究项目的摘要 血红素铁依赖性酶的标志之一是氧化反应的广泛氧化反应 催化其高价值铁氧化物种。但是，一个难题是每种蛋白质通常 仅促进特定类型的反应。形成后如何确定反应类型 关键氧化剂仍然是一个悬而未决的问题，其答案对基本的影响有影响 了解酶催化以及从头酶设计和蛋白质工程。因为 酪氨酸是天然产品的重要组成部分，该项目着重于机械 三种血红素依赖性酪氨酸氧化酶的表征。这些酶中的每一个都采用 单核血红素辅因子可氧化其基于酪氨酸的底物。有趣的是，细胞色素P450 蛋白质，结核分枝杆菌的CYP121，催化异常氧化碳碳交叉 偶联反应而不是更常见的羟基化反应。我们发现SFMD是新的 色氨酸二加氧酶超家族的成员，该酶在促进区域选择性单样氧化的成员 甲基化的酪氨酸底物。过氧化物酶LMBB2与 组氨酸而不是半胱氨酸的轴向配体。这些酶不仅催化基于酪氨酸的氧化 反应，但它们也与抗菌药物开发有关。鉴于血红素的相似之处 基于氧化剂和底物的结构，出现了一个不可避免的问题，并将回答 这项有关决定这些酶催化活性的治疗因素的研究。目标 ＃1，我们将确定CYP121的机械和结构特征。使用一电池 光谱和结构方法加上合成探针，我们将推出一种新颖的碳 由P450酶介导的碳耦合机制。在AIM＃2中，我们将表征结构 SFMD的机制，重点是底物如何将其定位在铁结合的氧化剂上 以及催化中间体的捕获。我们已经确定这种蛋白质是一种新颖的血红素 - 基氧酶。 AIM＃3将着重研究由LMBB2催化的过氧化物酶反应 通过L-酪氨酸羟基化负责L-3,4-二羟基苯胺（L-DOPA）形成。我们 将利用小分子探针询问机械途径。对这些的深入分析 三个相关的催化系统将检验我们关于血红素结合氧化剂的假设 生成并指向芳香基底物，揭示 在更高级别上看似无关的超家族的血红素酶，并发展基础 机制进一步协助合理的药物设计和发现过程。