在传感器中的全负合的能量 S. aureus CzrArA
Nicholas E Grossoehme1, David P Giedroc
1Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, USA.
Journal of the American Chemical Society
|December 10, 2009
概括
黄球菌CzrA对的感知在DNA结合中表现出负合作性,这是由连续的Zn2+) 离子结合时明显的热力学和结构变化所驱动的. 这一规定影响了金属调节蛋白的功能.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- 整体调节的蛋白质通过结构变化控制细胞过程.
- 黄金葡萄球菌的CzrA蛋白是一种感应抑制剂,它与DNA结合.
- 了解CrA-DNA相互作用的热力学对于金属调节蛋白研究至关重要.
研究的目的:
- 为了研究离子 (Zn(2+)) 与 CzrA 抑制器结合的全球热力学.
- 阐明在CzrA-DNA运营者 (CzrO) 复合体形成中的全性负调节机制.
- 描述自由CzrA和CzrA-CzrO复合体之间的能量和动态差异.
主要方法:
- 异热定位热量计 (ITC) 用于测量结合热力学.
- 热力学参数 (ΔG, ΔH, ΔS, ΔCp) 已被分析为连续的Zn2+结合.
- 从热力学数据推断出结构和动态变化.
主要成果:
- Zn(2+) 在两个步骤中与负同otropic合作性 (Δ(ΔG) = 1.8 kcal mol(-1)) 结合自由的CzrA.
- 第一次Zn2+) 结合涉及到更大的贡献,并表明了适度的结构转变.
- 第二个Zn(2+) 结合灭了内部动态,推动了合作.
- 与CzrA*CzrO复合体结合的Zn(2+) 也显示出负合作性 (Δ(ΔG) = 1.3 kcal mol(-1)) 但具有不同的能量和最小的结构变化.
- 强烈的异质负相关性来自不同的apo-CzrA和CzrA*CzrO结构.
结论:
- 这项研究揭示了CrA-DNA结合中负合作性的热力学基础.
- 在Zn ((2+) 结合时,不同的结构和动态转换调节了CzrA的功能.
- 这些发现提供了对金属调节蛋白的全性机制的见解.
相关概念视频
Allosteric Proteins-ATCase
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 pathway,...
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 pathway,...
Allosteric Regulation
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...
Allosteric Regulation
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...
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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...
Cooperative Allosteric Transitions
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...
Cooperative Allosteric Transitions
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...


