聚胺生物合成的碳素胺脱酶的动态和结构特征
Danielle F Lee1, Niko Atencio1, Shade Bouchey1
1Department of Chemistry and Biochemistry, Fort Lewis College, Durango, Colorado, USA.
The Journal of biological chemistry
|July 12, 2023
概括
肠道微生物通过一种独特的途径产生必需的多氨酸. 研究人员特征了碳素胺脱酶 (CASDH),揭示了其结构和动力学,这对于理解微生物聚胺合成至关重要.
科学领域:
- 生物化学 生物化学
- 微生物学 微生物学
- 结构生物学 结构生物学
背景情况:
- 多氨酸是生命的各个领域中发现的重要化合物.
- 肠道微生物通过一条不同的途径合成聚氨酸,其中涉及氨酸脱酶 (CASDH).
- CASDH的功能和结构在很大程度上仍未被描述.
研究的目的:
- 从肠道微生物中阐明CASDH的结构和功能.
- 提供CASDH的第一个动态表征.
- 了解微生物聚胺生物合成途径.
主要方法:
- 使用X射线晶体学确定了Bacteroides fragilis CASDH的1.94 Å结构.
- 对BfCASDH和Clostridium leptum CASDH进行了稳定状态酶动力学.
- 动力参数 (kcat,kcat/Km) 通过使用各种基质和共酶来确定.
主要成果:
- 晶体结构显示BfCASDH具有类似于糖脱酶的三域折叠,但具有独特的活性位点.
- 动力学分析确定了丁素是可能的聚胺基质,NADPH是首选的辅酶.
- 在BfCASDH活动中观察到合作的证据.
- 碳盒胺被确定为反应产物.
结论:
- 这项研究提供了CASDH的第一个结构和运动特征.
- 这些发现揭示了微生物聚胺生产中的一个关键酶.
- 了解CASDH对于探索肠道微生物聚胺在人类健康中的作用至关重要.
相关概念视频
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
01:29Amino Acid Biosynthetic Pathways
38
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...
38
01:28Biosynthesis of Nucleic Acids
84
Nucleic acid biosynthesis is a fundamental biochemical process that produces the purine and pyrimidine nucleotides essential for DNA and RNA synthesis. This pathway maintains a balanced nucleotide pool, preventing imbalances that could jeopardize genetic integrity and cellular function. Given the crucial role of nucleotides, their synthesis is tightly regulated to ensure proper cellular homeostasis.Purine BiosynthesisThe biosynthesis of purine nucleotides begins with ribose-5-phosphate, a...
84
01:23Aldehydes and Ketones with Amines: Imine Formation Mechanism
5.8K
Imine formation involves the addition of carbonyl compounds to a primary amine. It begins with the generation of carbinolamine through a series of steps involving an initial nucleophilic attack and then several proton transfer reactions. The second part includes the elimination of water, as a leaving group, to give the imine.
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
5.8K
01:28Amides to Carboxylic Acids: Hydrolysis
3.4K
Amides can undergo either acid-catalyzed hydrolysis or base-promoted hydrolysis through a typical nucleophilic acyl substitution. Each hydrolysis requires severe conditions.
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
3.4K
01:25Basicity of Heterocyclic Aromatic Amines
6.1K
Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
6.1K