Contribution of Ligand Sets to Oxygen Activation in Iron-dependent Biocatalysts

配体组对铁依赖性生物催化剂中氧活化的贡献

• 批准号: 10659063
• 负责人: Yifan Wang
• 金额: $ 37.75万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10659063
• 关键词: Active Sites; Address; Aerobic; Alkenes; Binding; Biomimetics; Cell Respiration; Chemistry; Complex; Dioxygen; Engineering; Environment; Enzymes; Funding; Heme; Individual; Investigation; Iron; Isomerism; Kinetics; Knowledge; Life; Ligands; Ligation; Mediating; Metabolic Biotransformation; Molecular; Mycoses; Nature; Nitrogen; Organism; Outcome; Oxidants; Oxygen; Oxygenases; Pathway interactions; Process; Production; Reaction; Research; Scaffolding Protein; Structure; System; Tryptophan; Visual impairment; catalyst; comparative; design; metalloenzyme; porphyrin a; singlet state; visual cycle

Project Summary The central theme of this project is dioxygen activation for C-H/C-C bond functionalization, which is fundamental for aerobic life. Molecular oxygen is a powerful oxidant, but the reaction with ground-state singlet molecules is kinetically unfavorable due to the spin-forbidden nature. To harness the oxidizing power of oxygen and circumvent the unregulated production of reactive oxidative species, metalloenzymes are frequently employed by aerobic organisms to activate oxygen and manipulate biomolecules. Heme and non-heme iron enzymes are two of the most ubiquitous and potent natural catalysts. Representative systems have been well characterized with near-complete mechanistic delineation. However, catalytic pathways of iron-dependent oxygenases with less common ligand sets lack description, and studies emphasizing an individual system do not often consider the intrinsic differences between heme and non-heme coordination. A holistic picture to systematically compare these two systems regarding oxygen activation and reactivity is deficient in the field. This project desires to fill the knowledge gap by investigating how the ligand sets contribute to reaction outcomes and why a particular system exploits one coordination over the other for a specific reaction. An apparent challenge of direct comparison is the massive variability between systems: the selection of ligand donors, active site environment, substrate-binding mode, and overall protein scaffold. To simplify the coordination environment for an unbiased comparison, two unique multifunctional oxygenases are chosen, each with an iron center ligated only by nitrogen-donors. One is a His-ligated heme- dependent enzyme responsible for pyrrolnitrin production, promoting remarkable rearrangement of a tryptophan derivative. The other is a non-heme iron-dependent enzyme crucial for the visual cycle, which catalyzes oxidative alkene cleavage and isomerization using a 4-His ligated ferrous iron. The catalytic mechanisms and structure-function correlations of both enzymes are poorly understood and the ligand sets are rarely found to mediate oxygenation reactions. Over the five-year funding period, we will comparatively investigate the heme and non-heme systems to decode how the atypical ligand sets promote the unusual biotransformations and how oxygen activation is tuned by the presence or absence of a porphyrin ring. Ultimately, the proposed research will leverage the understanding of iron-oxygen chemistry, inspire the design of biomimetic complexes and engineered biocatalysts, and advance the potential for biomedical treatments for fungal infection and impaired vision.

项目摘要 该项目的中心主题是C-H/C-C键功能化的二氧化激活，这对于 有氧生活。分子氧是一种强大的氧化剂，但与地面单线分子的反应在动力学上是 由于旋转的性质而不利。利用氧气的氧化能力并绕过不受管制的 产生反应性氧化物种，金属酶经常被有氧生物激活氧气 并操纵生物分子。血红素和非血红素铁酶是最普遍，有效的自然催化剂之一。 代表性系统已经通过几乎完整的机械划定进行了很好的特征。但是，催化 铁依赖性氧酶的途径较少常见的配体套件缺乏描述，并强调了 单个系统通常不考虑血红素和非血红素协调之间的内在差异。整体 图片到系统地比较有关氧激活和反应性的这两个系统在现场缺陷。这 项目希望通过调查配体集合如何促进反应结果以及为什么一个原因来填补知识差距 特定的系统利用一个协调对另一个进行特定反应。直接比较的明显挑战 系统之间的巨大差异是：配体供体的选择，活动现场环境，底物结合模式， 和整体蛋白质支架。为了简化协调环境以进行公正的比较，两个独特的 选择多功能氧酶，每个氧合酶仅由氮含量的铁心中心。一个是用他的绑扎的血红素 - 依赖性酶负责吡咯并非产生吡咯并促进色氨酸衍生物的显着重排。 另一种是视觉周期至关重要的非血红素依赖性酶，可催化氧化烯烃的裂解和 使用4-HIS连接的亚铁铁。两者的催化机制和结构功能相关性 酶的理解很少，很少发现配体套件介导氧合反应。在五年中 资金期，我们将相对研究血红素和非血红素系统，以解码非典型配体如何设置 促进异常的生物转化以及如何通过存在或不存在卟啉环调节氧气活化。 最终，拟议的研究将利用对铁氧化学的理解，激发设计的设计 仿生复合物和工程生物催化剂，并推动生物医学治疗真菌感染的潜力 和视力受损。