Multinuclear Dioxygen-Utilizing Copper Enzymes: Diverse Roles for Aromatic Redox Active Amino Acids

多核双氧利用铜酶：芳香族氧化还原活性氨基酸的多种作用

• 批准号: 10714992
• 负责人: Shabnam Hematian
• 金额: $ 34.31万
• 依托单位: UNIVERSITY OF NORTH CAROLINA GREENSBORO
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2028-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10714992
• 关键词: Active Sites; Address; Adopted; Aerobic; Amino Acids; Aromatic Amino Acids; Biochemistry; Bioinorganic Chemistry; Cell Respiration; Coenzymes; Copper; Coupled; Couples; Dioxygen; Electrons; Enzymes; Iron; Life; Mediating; Metabolic; Metals; Molecular; Nature; Nuclear; Oxidants; Oxidation-Reduction; Oxygen; Peptides; Planet Earth; Play; Positioning Attribute; Process; Protons; Reaction; Role; Side; Site; Source; Tryptophan; Tyrosine; Water; cofactor; copper oxidase; cytochrome c oxidase; design; enzyme mechanism; fundamental research; metalloenzyme; oxidation

PROJECT SUMMARY Aerobic life on earth harnesses the oxidizing power of molecular oxygen (O2) through a diverse range of enzyme cofactors and employs that high oxidation potential to mediate numerous oxidative transformations during metabolic functions. Many of these cofactors are coupled binuclear sites consisting of two metal centers such as copper and iron in close proximity. This proposal details fundamental research in the field of bioinorganic chemistry and aims to address several intriguing questions about the potential roles of redox aromatic active amino acids such as tyrosine and tryptophane chains in the enzyme mechanism and function. We identified three different classes of O2-utilizing copper enzymes including cytochrome c oxidase (CcO) which reduces O2 to water, multicopper oxidase (MCO) which couples that reaction to four one-electron oxidations of the substrates, and a new class of copper enzymes called BURP domain cyclases which catalyze 2-electron oxidative macrocyclization of the Tyr/Trp chains in peptide substrates.The use of O2 as either a substrate or terminal electron acceptor has been established in these enzymes except for the BURP domain enzymes which is yet to be confirmed. In all three classes, appropriately tuned and positioned Tyr/Trp chains play different roles either as an integral part of the active site (i.e., CcO) or they may be assigned a mediatory role to provide an alternative path for oxidation of the more challenging substrates (i.e., MCO). They may even act as the direct substrate for the active site (i.e., Cu-dependent BURP domain cyclases). In all cases, despite the diverse use of these chains, their main function is to delicately supply the electron/proton needed for the O2 reduction. How are these residues designed/optimized for a particular function? What are the similarities and differences between these enzymes? Our studies aim to reveal the potential role of these Tyr/Trp chains play in enzymatic function and mechanism and address some of the questions about copper biochemistry and aerobic metabolism.

项目概要 地球上的有氧生命通过多种方式利用分子氧 (O2) 的氧化能力 酶辅因子并利用高氧化电位介导许多氧化转化 在代谢功能期间。许多这些辅因子是由两个金属中心组成的耦合双核位点 例如铜和铁的距离很近。该提案详细介绍了该领域的基础研究 生物无机化学，旨在解决有关氧化还原潜在作用的几个有趣问题 芳香族活性氨基酸如酪氨酸和色氨酸链在酶的机制和功能中的作用。 我们鉴定了三种不同类别的利用 O2 的铜酶，包括细胞色素 c 氧化酶 (CcO) 将 O2 还原成水，多铜氧化酶 (MCO) 将该反应与四个单电子耦合 底物的氧化，以及一类新的铜酶，称为 BURP 结构域环化酶，可催化 肽底物中 Tyr/Trp 链的 2 电子氧化大环化。使用 O2 作为 除 BURP 结构域外，这些酶中已建立底物或末端电子受体 酶，尚未得到证实。 在所有三个类别中，适当调整和定位的 Tyr/Trp 链发挥不同的作用，或者作为 活性位点（即 CcO）的组成部分，或者它们可能被赋予中介作用以提供替代方案 更具挑战性的底物（即 MCO）的氧化途径。它们甚至可以作为直接基质 活性位点（即 Cu 依赖性 BURP 结构域环化酶）。在所有情况下，尽管这些方法的用途多种多样 链，它们的主要功能是微妙地提供 O2 还原所需的电子/质子。这些怎么样 为特定功能设计/优化的残基？这些之间有什么相同点和不同点 酶？我们的研究旨在揭示这些酪氨酸/色氨酸链在酶功能中的潜在作用和 机制并解决有关铜生物化学和有氧代谢的一些问题。