三铜μ-Oxo/Hydroxo/Aqua复合体中的质子合电子转移的热力学
Saikat Mondal1, Weiyao Zhang1, Shiyu Zhang1
1Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States.
Journal of the American Chemical Society
|May 21, 2024
概括
这项研究揭示了多铜氧化酶 (MCO) 如何在三铜位点使用质子合电子转移 (PCET) 有效地减少氧气. 了解这些热力学解释了MCOs
科学领域:
- 生物化学
- 生物有机化学
- 酶机制
背景情况:
- 多铜氧化酶 (MCOs) 是关键的酶,通过四电子,四质子过程催化氧化成水.
- 在MCO中的三铜活性位点是这种氧降解反应 (ORR) 的核心,涉及复杂的质子合电子转移 (PCET) 机制.
- 在三铜集群中阐明控制PCET的热力学原理是了解MCO效率和预防氧化损伤的关键.
研究的目的:
- 确定合成三铜和水复合物的O-H键解离自由能量 (BDFEs) 和pKa值.
- 模拟MCO中的三铜活性位点,并研究PCET通路的热力学.
- 确定在氧降解过程中最不容易分解的PCET途径.
主要方法:
- 合成各种三铜和水化合物,作为MCO活性位点的结构和功能模型.
- 对关键中间体的O-H键解离自由能量 (BDFEs) 的确定
- 在二次协调球中测量pKa值,以弥合氧/水性联体和N-H基因.
主要成果:
- 在提议的ET-PT-ET-PT-ET路径上,三铜中间体显示了适度的BDFE (O-H) 值 (53.057.1 kcal/mol).
- 不在此途径上的中间体显示显著更高的 (78.1 kcal/mol) 或更低的 (44.7 kcal/mol) BDFE ((O-H) 值.
- 桥梁OH/OH2基因的pKa在每氧化状态上大大增加 (816单位),而二次球体N-H基因的增加则较小 (约216单位). 5个单位).
结论:
- 与二次球体相比,三铜中心的pKa增加更急,这有助于质子转移.
- 已识别的PCET途径在热力学上有利,不太容易分解,这解释了MCO的稳定性.
- 这些发现突出了三铜中心的最佳设计,以实现高效和稳定的氧降解反应.
相关概念视频
Electron Transport Chain: Complex III and IV
7.4K
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
7.4K
Thermal and Photochemical Electrocyclic Reactions: Overview
2.3K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.3K
The Supercomplexes in the Crista Membrane
2.5K
The mitochondrial cristae membrane is the primary site for the oxidative phosphorylation (OXPHOS) process of energy conversion mediated through respiratory complexes I to V. These complexes have been widely studied for decades, and it has been proven that they form supramolecular structures called respiratory supercomplexes (SC). These higher-order complexes may be crucial in maintaining the biochemical structure and improving the physiological activity of the individual complexes while...
2.5K
Electron Transport Chain: Complex I and II
13.0K
The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce cytotoxic reactive oxygen species (ROS) due to the large electron flow during oxidative phosphorylation. While Complex I is one of the primary sources of superoxide radicals, ROS production by Complex II is uncommon and may only be observed in cancer cells with mutated complexes.
ROS generation is regulated and maintained at moderate levels necessary...
ROS generation is regulated and maintained at moderate levels necessary...
13.0K
The Electron Transport Chain
16.6K
The electron transport chain or oxidative phosphorylation is an exothermic process in which free energy released during electron transfer reactions is coupled to ATP synthesis. This process is a significant source of energy in aerobic cells, and therefore inhibitors of the electron transport chain can be detrimental to the cell's metabolic processes.
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q...
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q...
16.6K
Redox Equilibria: Overview
563
A reduction-oxidation reaction is commonly called a redox reaction. In a redox reaction, electrons are transferred from one species to another rather than being shared between or among atoms. The reducing agent or reductant is the species that loses electrons and gets oxidized in the process. The species that gains electrons and gets reduced in the process is the oxidizing agent or oxidant. Redox reactions are represented as two separate equations called half-reactions, where one equation...
563
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)

