![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)
来自Geobacter metallireducens的cytochrome c酸盐还原酶NrfA-1中的一个不寻常的活性位点结构
Lukas Denkhaus1, Fanny Siffert1, Oliver Einsle1
1Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg im Breisgau, Germany.
FEMS microbiology letters
|July 17, 2023
概括
将酸盐降解为氨 (DNRA) 在生态系统中保留. 研究人员特征了一种新型酶,GmNrfA,揭示了一种独立于的结构,其功能至关重要的酸残留物.
科学领域:
- 生物地化学气循环
- 微生物的新陈代谢
- 结构生物学 结构生物学
背景情况:
- 溶解性酸盐降解为氨 (DNRA) 是一个关键的循环途径,保存作为.
- 酶pentahaem细胞染色体c酸盐减少酶 (NrfA) 调解了DNRA的最后一步.
- 最近发现了一种缺乏的新型NrfA子类,这促使进一步调查.
研究的目的:
- 从结构和功能上对Geobacter metallireducens (GmNrfA) 的NrfA进行表征.
- 研究一种独特的活性部位残留物在GmNrfA的催化活性和特性中的作用.
主要方法:
- 在大肠杆菌中产生催化活性GmNrfA的重组生成.
- 通过X射线晶体学,以1.9 Å分辨率确定GmNrfA的三维结构.
- 局部定向突变发生,以创建和分析D80A和D80N变体.
主要成果:
- 通过重组产生GmNrfA并确定其结构,确认它是独立于的NrfA.
- 在活性部位发现了一种前所未有的阿斯巴酸盐残留物 (D80),它改变了基质通道,并使硫酸盐不敏感.
- 突变变种D80A和D80N的催化活性显著降低,突出显示了D80的重要性.
结论:
- GmNrfA代表了一种具有独特活性位点配置的新型独立NrfA.
- D80残留在GmNrfA的催化,基质结合和潜在的抑制剂耐药性中发挥着关键作用.
- 这项研究扩大了我们对NrfA多样性和DNRA控制机制的理解.
相关概念视频
01:30Anoxygenic Photosynthesis
53
Anoxygenic photosynthesis is a phototrophic process that captures light energy to drive carbon fixation without producing molecular oxygen. Unlike oxygenic photosynthesis, which utilizes water as an electron donor and releases oxygen, anoxygenic phototrophs use alternative electron donors such as hydrogen sulfide (H₂S), elemental sulfur (S⁰), or thiosulfate (S₂O₃²⁻). This process is carried out by diverse groups of bacteria, including purple bacteria, green...
53
01:46Electron Transport Chain: Complex I and II
14.5K
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...
14.5K
01:43Electron Transport Chain: Complex III and IV
7.6K
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...
7.6K
01:19Allosteric Proteins-ATCase
5.8K
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...
5.8K
01:22Inorganic Nitrogen Assimilation
49
Nitrogen is an essential element in biological systems, forming a crucial component of proteins, nucleic acids, and other cellular constituents. Many bacteria and archaea acquire nitrogen in the form of nitrate (NO₃⁻) or ammonia (NH₃), which are then assimilated into biomolecules through specific enzymatic pathways.Assimilatory Nitrate ReductionWhen nitrate enters the cell, it undergoes a two-step reduction process known as assimilatory nitrate reduction. Initially, the enzyme...
49
01:28Carbon-dioxide Fixation
42
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...
42