Monooxygenase/arylamine N-oxygenase activity within a single non-heme diiron enzyme (MiaE)

单一非血红素二铁酶 (MiaE) 内的单加氧酶/芳胺 N-加氧酶活性

• 批准号: 1709369
• 负责人: Brad Pierce
• 金额: $ 41.94万
• 依托单位: University of Texas at Arlington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1709369&HistoricalAwards=false
• 关键词: Monooxygenase; arylamine; oxygenase; activity; within

With this award granted by the National Science Foundation-Chemistry Division, Chemistry of Life Processes Program, Dr. Brad S. Pierce at The University of Texas at Arlington will investigate the factors influencing the extent of biological oxidations. The proposed activities provide an opportunity to better understand structural factors driving biological oxidations and thus provide a framework for the rational design of biologically-inspired or bioengineered oxidation catalysts. Oxidations result in a net transfer of electrons from the initial molecule (or substrate) to molecular oxygen. From an accounting point of view, the "extent" of an oxidation can be defined as the number of electrons transferred. It has been previously noted that changes in structure around iron dramatically influence the extent of substrate oxidation by catalysts. The proposed biochemical studies utilize an iron catalyst to compare the factors directing 2- and 6-electron oxidations within a single, simplified platform. Beyond training for graduate/undergraduate students in biochemistry, biophysics and chemical catalysis, broader impact activities for this award include training and practical experience in scientific communication for the PI and students (undergraduate and graduate) participating in NSF-supported activities. Non-heme diiron enzymes are a ubiquitous family of enzymes capable of catalyzing an amazing diversity of biological oxidations. Among these enzymes, it has been observed that single amino acid perturbations within the first Fe-coordination sphere have a profound impact on the nature of transient intermediates produced following O2-activation and the extent of substrate oxidation. For example, within the bacterial multicomponent monooxygenase (BMM) superfamily, the hydroxylase component diiron site is coordinated by 2-histidine and 4-carboxylate (Asp or Glu) residues [2-His/4-carboxylate]. The reduced (diferrous) active sites of these enzymes are capable of reductively activating molecular oxygen to catalyze the 2-electron oxidation of its specific substrate. By contrast, a small number of enzymes have been identified which contain an additional His-residue coordinated to one of the two Fe-sites; resulting in a [3-His/4-carboxlate] diiron cluster. Among these are the arylamine N-oxygenase class of non-heme diiron enzymes AurF and CmlI. These enzymes catalyze a remarkable 6-electron oxidation of arylamine substrates to yield a nitroaryl product. The proposed studies utilize an unusual non-heme tRNA-hydroxylase isolated from S. typhimurium (St MiaE) to compare the relevant factors directing (6-electron) arylamine N-oxygenase and (2-electron) monooxygenase chemistry within a single, enzymatic platform. This comparison is made possible by a single amino acid substitution (L199H) within the St MiaE active site which yields a [3-His/4-carboxylate] first Fe-coordination sphere and imparts 6-electron arylamine N-oxygenase activity. Beyond training for graduate/undergraduate students in biochemistry, biophysics and chemical catalysis, broader impact activities for this award include training and practical experience in scientific communication for the PI and students (undergraduate and graduate) participating in NSF-supported activities.

该奖项由美国国家科学基金会化学部生命过程化学计划授予，布拉德S。德克萨斯大学阿灵顿分校的皮尔斯将研究影响生物氧化程度的因素。 拟议的活动提供了一个机会，更好地了解结构因素驱动生物氧化，从而提供了一个框架，合理设计的生物启发或生物工程氧化催化剂。 氧化导致电子从初始分子（或底物）向分子氧的净转移。 从计算的角度来看，氧化的“程度”可以定义为转移的电子数。 以前已经注意到，铁周围结构的变化显著影响催化剂对底物的氧化程度。 拟议的生物化学研究利用铁催化剂，在一个单一的，简化的平台内比较指导2-和6-电子氧化的因素。 除了为生物化学，生物物理学和化学催化的研究生/本科生提供培训外，该奖项更广泛的影响活动包括为参加NSF支持活动的PI和学生（本科生和研究生）提供科学交流方面的培训和实践经验。非血红素二铁酶是一个普遍存在的酶家族，能够催化生物氧化的惊人多样性。 在这些酶中，已经观察到，在第一Fe-配位球内的单个氨基酸扰动对以下O2-活化和底物氧化的程度产生的瞬态中间体的性质具有深远的影响。 例如，在细菌多组分单加氧酶（BMM）超家族中，羟化酶组分二铁位点由2-组氨酸和4-羧酸（Asp或Glu）残基[2-His/4-羧酸]配位。 这些酶的还原（二价铁）活性位点能够还原活化分子氧以催化其特定底物的2-电子氧化。 相比之下，已经鉴定了少量的酶，其含有与两个Fe位点之一配位的额外的His残基;导致[3-His/4-羧酸根]二铁簇。 其中包括芳胺N-加氧酶类的非血红素二铁酶AurF和CmlI。 这些酶催化芳胺底物的显著6电子氧化以产生硝基芳基产物。 这项研究利用了一种从S.鼠伤寒沙门氏菌（St MiaE）中进行比较，以比较在单一酶平台内指导（6-电子）芳胺N-加氧酶和（2-电子）单加氧酶化学的相关因子。 通过St MiaE活性位点内的单个氨基酸取代（L199 H）使得这种比较成为可能，该取代产生[3-His/4-羧酸]第一Fe-配位球并赋予6-电子芳胺N-加氧酶活性。 除了为生物化学，生物物理学和化学催化的研究生/本科生提供培训外，该奖项更广泛的影响活动包括为参加NSF支持活动的PI和学生（本科生和研究生）提供科学交流方面的培训和实践经验。

项目成果

Hydrogen Peroxide Disproportionation with Manganese Macrocyclic Complexes of Cyclen and Pyclen.

Cyclen 和 Pyclen 的锰大环配合物的过氧化氢歧化。

• DOI: 10.1039/c9qi01509d
• 发表时间: 2020
• 期刊: Inorganic chemistry frontiers
• 影响因子: 7
• 作者: Freire,DavidM;Beeri,Debora;Pota,Kristof;Johnston,HannahM;Palacios,Philip;Pierce,BradS;Sherman,BenjaminD;Green,KaylaN
• 通讯作者: Green,KaylaN

Electron paramagnetic spectrum of dimanganic human serum transferrin.

• DOI: 10.1016/j.poly.2021.115224
• 发表时间: 2021-04
• 期刊: Polyhedron
• 影响因子: 2.6
• 作者: Molly Lockart;K. Edwards;J. Vincent;B. Pierce