光系统II中氧合质子动态的分子原理
Friederike Allgöwer1, Ana P Gamiz-Hernandez1, A William Rutherford2
1Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.
Journal of the American Chemical Society
|April 14, 2022
概括
光系统II使用氧化还原触发的质子转移和离子对动力学来氧化水,释放氧气. 这种涉及Mn4Ca集群和Tyrz的机制解决了生物能源领域长期存在的挑战.
科学领域:
- 生物化学
- 光合作用研究
- 生物有机化学
背景情况:
- 光系统II (PSII) 对于氧化光合作用至关重要,催化光驱动的水氧化.
- 在PSII中精确氧化水的机制仍然是化学研究中的一个重大挑战.
- 了解PSII功能对于人工光合作用和生物能源应用至关重要.
研究的目的:
- 阐明光系统II催化水氧化的详细机制.
- 研究氧化还原触发的质子转移和离子对动态在催化循环中的作用.
- 将计算结果与X射线自由电子激光 (XFEL) 研究的实验数据联系起来.
主要方法:
- 采用了多层次的量子和经典模拟.
- 氧化还原活性氨酸 (Tyrz) 的氧化及其对质子转移的影响的分析.
- 研究离子对动力学 (Asp61/Lys317) 和质子路径.
- 计算模型与最近的XFEL实验数据进行比较.
主要成果:
- 在Mn4Ca集群和埋藏的离子对之间催化氧化还原触发的质子转移.
- Tyrz 的氧化促进了从 Ca2+ 结合的水分子 (W3) 到 Asp61 的质子转移.
- 通过Mn4Ca集群的水联体,W3迁移和随后的质子转移导致O2形成.
- 该机制涉及水合变化,离子对动力学和电场调制.
结论:
- 在PSII中提出了一种氧化还原合质子化机制.
- 这些发现揭示了氧化还原事件,质子转移和蛋白质动态的关键相互作用.
- 阐明的机制与其他生物能量酶有相似之处,为生物能量转化提供了洞察力.
更多相关视频
07:10Purification of Active Photosystem I-Light Harvesting Complex I from Plant Tissues
Published on: February 3, 2023
1.3K
08:40Separation of Spinach Thylakoid Protein Complexes by Native Green Gel Electrophoresis and Band Characterization using Time-Correlated Single Photon Counting
Published on: February 14, 2019
8.4K
相关概念视频
Photosystem II
73.2K
The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ultimately to photosystem I (PSI) through the electron transport chain. The pigments responsible for caputirng the light energy in photosystems include chlorophyll a, chlorophyll b, and carotenoids.
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment...
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment...
73.2K
Photosystem I
65.0K
Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
65.0K
Photosystems
5.1K
Photosystems are multiprotein complexes that form the functional units of photosynthesis in plants, algae, and cyanobacteria. They are found embedded in the membrane of tiny sac-like structures called thylakoids placed inside the chloroplast.
Functioning of Photosystems
Photosystems contain many pigment molecules, such as chlorophylls and carotenoids, arranged in a particular organization across two domains — the antenna complex and the reaction center. The main aim of the pigment...
Functioning of Photosystems
Photosystems contain many pigment molecules, such as chlorophylls and carotenoids, arranged in a particular organization across two domains — the antenna complex and the reaction center. The main aim of the pigment...
5.1K
The Z-Scheme of Electron Transport in Photosynthesis
10.6K
The light reactions of photosynthesis assume a linear flow of electrons from water to NADP+. During this process, light energy drives the splitting of water molecules to produce oxygen. However, oxidation of water molecules is a thermodynamically unfavorable reaction and requires a strong oxidizing agent. This is accomplished by the first product of light reactions: oxidized P680 (or P680+), the most powerful oxidizing agent known in biology. The oxidized P680 that acquires an electron from the...
10.6K
The Photochemical Reaction Center
4.3K
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
4.3K
Oxygenic Photosynthesis
242
Oxygenic photosynthesis is a fundamental process in which light energy is harnessed to drive the oxidation of water, leading to the production of molecular oxygen (O₂), adenosine triphosphate (ATP), and nicotinamide adenine dinucleotide phosphate (NADPH). This process is essential for sustaining aerobic life on Earth and is primarily carried out by cyanobacteria, algae, and plants. The core of oxygenic photosynthesis lies in the thylakoid membranes, where chlorophyll pigments facilitate...
242
