甲生成电子分裂和CO2固定酶的三兆复合体
Tomohiro Watanabe1, Olivia Pfeil-Gardiner2, Jörg Kahnt3
1Microbial Protein Structure Group, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
概括
研究人员描述了Fdh-Hdr-Fmd酶复合体,对于甲基生成至关重要. 这种复合物有效地使用甲酸盐和F420减少二氧化碳 (CO2),揭示了性甲原体的保存机制.
科学领域:
- 生物化学
- 微生物学
- 结构生物学
背景情况:
- 甲生成的初步步骤包括将二氧化碳 (CO2) 减少为甲甲,由甲甲脱酶 (Fmd) 催化.
- 这种CO2的减少需要强烈的减少电子,通常由异硫化还原酶 (Hdr) 与酶或形式脱酶 (Fdh) 通过基于黄素的电子分支提供.
研究的目的:
- 为了阐明来自*Methanospirillum hungatei*的Fdh-Hdr-Fmd复合物的酶和结构特性.
- 了解这个复合体内的电子转移和CO2减少的机制.
主要方法:
- 用于描述Fdh-Hdr-Fmd复合物的催化活性的酶学试验.
- 对Fdh-Hdr-Fmd复合物的结构确定.
- 研究电子转移途径,包括聚二氧化 (FmdF) 和基于黄素的电子分叉作用.
主要成果:
- 来自*M. hungatei*的Fdh-Hdr-Fmd复合体的特征,证实了其在利用格式和减少F420减少中催化CO2的作用.
- 在HdrA的形态变化被确定为介导电子分叉的关键.
- 显示Polyferredoxin FmdF可以直接将电子转移到CO2的减少部位,这表明依赖于甲素的黄素基电子分支独立于自由的费雷多克辛.
结论:
- 这项研究揭示了Fdh-Hdr-Fmd复合体启动甲基生成的详细机制.
- 这些发现突显了FmdF的直接电子转移以及HdrA在电子分叉中的构造变化的关键作用.
- 结构保护表明这种复合物在性甲基中广泛存在.
相关概念视频
Electron Transport Chain: Complex III and IV
8.3K
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...
8.3K
Electron Transport Chain: Complex I and II
15.4K
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...
15.4K
Carbon-dioxide Fixation
195
Carbon dioxide fixation in prokaryotes enables the assimilation of inorganic carbon into organic molecules, supporting biosynthetic pathways, sustaining ecosystems, and contributing to the global carbon cycle. It also has industrial applications in carbon capture and bioproduct synthesis. Autotrophic organisms rely on this process to utilize CO₂ as a carbon source in diverse environments.The Calvin CycleThe Calvin cycle is the most widespread carbon fixation mechanism, primarily used by...
195
The Supercomplexes in the Crista Membrane
2.6K
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...
2.6K
Electron Transport Chains
107.1K
The final stage of cellular respiration is oxidative phosphorylation that consists of two steps: the electron transport chain and chemiosmosis. The electron transport chain is a set of proteins found in the inner mitochondrial membrane in eukaryotic cells. Its primary function is to establish a proton gradient that can be used during chemiosmosis to produce ATP and generate electron carriers, such as NAD+ and FAD, that are used in glycolysis and the citric acid cycle.
The ETC is comprised of...
The ETC is comprised of...
107.1K
Metabolism of Chemolithotrophs
337
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation.
337


