蓝藻细菌α-carboxysome碳酸无水酶被鲁比斯科基质RuBP调节
Sacha B Pulsford1,2, Megan A Outram3, Britta Förster3
1ARC Centre of Excellence in Synthetic Biology, Sydney, NSW, Australia.
Science advances
|May 10, 2024
概括
菌碳缩机制 (CCM) 使用碳素体来促进光合作用. 这项研究揭示了一个关键的酶,CsoSCA,被基质激活,澄清了它在这个重要过程中的功能.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 光合作用研究研究 光合作用研究
背景情况:
- 菌碳缩机制 (CCM) 对全球碳循环至关重要.
- 碳素酶体,蛋白质微分区,含有碳酸酶 (CA) 和鲁比斯科等酶,以增强二氧化碳的固定.
- 目前尚不清楚对碳素体CA的调节,特别是对alpha-cyanobacteria中的CsoSCA的调节.
研究的目的:
- 为了阐明Cyanobium sp.中的CsoSCA的结构和生物化学活性. 在PCC7001.1.上,我们可以使用PCC7001.
- 调查控制CsoSCA活动的监管机制.
- 为了确定alpha-carboxysomalCA的寡合状态和进化保存.
主要方法:
- 对CsoSCA的结构分析.
- 生物化学测试以确定酶动力学和全调节.
- 遗传学分析和局部定向的突变发生.
主要成果:
- *Cyanobium* CsoSCA是由Ribulose-1,5-bisphosphate,一个鲁比斯科基质,在所有质上激活的.
- 在CsoSCA中,它形成了一个二元体的六米三元体.
- 遗传学和突变数据表明,这种调节机制是蓝藻细菌α-carboxysomalCA的独特特征.
结论:
- 这项研究澄清了α-carboxysomalCA的功能性寡合体状态.
- 鉴定了核糖-1,5-双酸盐作为CsoSCA.的新型全激活剂.
- 进步了解全球占主导地位的蓝藻细菌中的光合作用调节.
相关概念视频
The Calvin Benson Cycle
4.5K
Ribulose 1,5- bisphosphate carboxylase/oxygenase (RuBisCo) is a critical enzyme that catalyzes carbon dioxide assimilation during photosynthesis. However, it is an inefficient enzyme, having an extremely slow catalytic rate. A typical enzyme can process about a thousand molecules per second; however, RuBisCo fixes only around three-carbon dioxides per second. Photosynthetic cells compensate for this slow rate by synthesizing very high amounts of RuBisCo, making it the most abundant single...
4.5K
Allosteric Regulation
57.9K
Allosteric regulation of enzymes occurs when the binding of an effector molecule to a site that is different from the active site causes a change in the enzymatic activity. This alternate site is called an allosteric site, and an enzyme can contain more than one of these sites. Allosteric regulation can either be positive or negative, resulting in an increase or decrease in enzyme activity. Most enzymes that display allosteric regulation are metabolic enzymes involved in the degradation or...
57.9K
Allosteric Proteins-ATCase
5.7K
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...
5.7K
Cooperative Allosteric Transitions
7.9K
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
7.9K
C4 Pathway and CAM
45.4K
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...
45.4K
Ligand Binding and Linkage
4.8K
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence...
4.8K


