在GatCAB中,氨通道将谷氨胺酶与转胺酶反应结合在一起
Akiyoshi Nakamura1, Min Yao, Sarin Chimnaronk
1Faculty of Advanced Life Sciences, Hokkaido University, Sapporo 060-0810, Japan.
概括
大多数细菌使用GatCAB酶产生谷氨-tRNA (Gln-tRNA). 晶体结构揭示了其活性位点和氨通道,解释了它如何合成Gln-tRNA.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- 谷氨-tRNA (Gln-tRNA) 合成在生命的各个领域都不同.
- 细菌经常使用一种间接的途径,涉及胺胺转移酶CAB (GatCAB) 作用于错基化Glu-tRNA.
研究的目的:
- 为了阐明金黄色葡萄球菌 GatCAB 的结构和机制.
- 了解细菌中Gln-tRNA合成的分子基础.
主要方法:
- 在各种状态下完整的GatCAB的X射线晶体学 (apo,结合体结合).
- 酶基质相互作用的生物化学分析.
主要成果:
- 晶体结构显示了两个不同的催化中心 (胺酶,转胺酶),由氨通道连接在一起.
- 确定了用于GatCAB识别的关键tRNA(Gln) 标识元素 (受体干基对,D循环).
- 提出了一种协调反应机制的模型.
结论:
- GatCAB的结构为细菌间接的Gln-tRNA合成途径提供了洞察力.
- 氨通道和tRNA标识元素对于高效的Gln-tRNA形成至关重要.
相关概念视频
C4 Pathway and CAM
Most plants use the C3 pathway for carbon fixation. However, some plants, such as sugar cane, corn, and cacti that grow in hot conditions, use alternative pathways to fix carbon and conserve energy loss due to photorespiration. Photorespiration is the process that occurs when the oxygen concentration is high. Under such conditions, the rubisco enzyme in the Calvin cycle binds O2 instead of CO2, which halts photosynthesis and consumes energy.
C4 Pathway
The C4 pathway is used by plants such as...
C4 Pathway
The C4 pathway is used by plants such as...
Phase II Reactions: Glutathione Conjugation and Mercapturic Acid Formation
Glutathione, a tripeptide made up of glutamate, cysteine, and glycine, is a critical player in the detoxification of drugs and xenobiotics via a process known as glutathione conjugation or mercapturic acid formation. This phase II biotransformation reaction involves the covalent binding of glutathione to a drug or its metabolite, enhancing the compound's water solubility and enabling its excretion.
Several distinctive characteristics distinguish glutathione conjugation from other phase II...
Several distinctive characteristics distinguish glutathione conjugation from other phase II...
Respiration Pathways
Cellular respiration is a fundamental metabolic process that enables organisms to generate energy from organic molecules. One of its central pathways is the tricarboxylic acid (TCA) cycle, also known as the Krebs cycle, which plays a crucial role in energy production and biosynthetic processes.Conversion of Pyruvate to Acetyl-CoAThe pyruvate generated from glycolysis undergoes oxidative decarboxylation by the pyruvate dehydrogenase complex, producing acetyl-CoA, one molecule of NADH, and one...
Amino Acid Catabolism
Microorganisms rely on proteins as an essential carbon and energy source, particularly in environments with limited polysaccharides or lipids. However, proteins are too large to cross the plasma membrane unaided, necessitating enzymatic degradation. Microbes secrete extracellular proteases and peptidases that hydrolyze proteins into peptides, which can then be transported across the membrane. Once inside the cell, intracellular proteases degrade these peptides into free amino acids, which...
Inorganic Nitrogen Assimilation
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 nitrate reductase...
Amino Acid Biosynthetic Pathways
Amino acid biosynthesis is essential for cell growth, protein synthesis, and metabolic regulation. Cells generate essential and non-essential amino acids from metabolic intermediates to sustain vital biological functions. These intermediates originate from key metabolic pathways: glycolysis, the tricarboxylic acid (TCA) cycle, and the pentose phosphate pathway. Important precursors include α-ketoglutarate, pyruvate, oxaloacetate, phosphoenolpyruvate, and erythrose-4-phosphate, which provide...


