在催化剂激活蛋白中对质的计算研究
Liwei Li1, Vladimir N Uversky, A Keith Dunker
1Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
Journal of the American Chemical Society
|November 29, 2007
概括
催化剂激活蛋白 (CAP) 在cAMP结合时切换其运动,导致DNA结合模块分离为空置的子单元. DNA 结合逆转了合作性,促进了转录激活的新型顺序到失序过渡机制.
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:
- 催化剂激活蛋白 (CAP) 是一个转录调节器,对基因表达至关重要.
- 在cAMP的约束中,CAP表现出负的合作性,这一现象尚未完全理解.
- 了解CAP的全性机制是破译细菌基因调节的关键.
研究的目的:
- 通过分子动力学模拟来研究CAP的全性机制.
- 阐明cAMP结合和DNA相互作用在CAP的形状变化中的作用.
- 提出一种用于CAP介导的转录激活的新机制.
主要方法:
- 广泛的明确溶剂分子动力学模拟 (135 ns) 的CAP.
- 使用动态交叉相关图和基本动态分析蛋白质动态.
- 使用MM-PBSA方法和正常模式分析进行免费能源计算.
主要成果:
- cAMP结合会诱导CAP运动的切换,并导致DNA结合模块在空置子单元中的解离.
- 计算显示在cAMP结合时稳定性和度增加,与实验数据一致.
- 存在的DNA逆转了合作性,促进了第二个cAMP分子的结合,主要是由于热效应.
结论:
- 提出了CAP的一种新型全性机制,涉及通过cAMP和DNA调解的顺序到失调的过渡.
- 这些发现挑战了CAP中以前的负面合作模式.
- 这项研究为转录激活的动态调节提供了新的见解.
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...
Ligand Binding and Linkage
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 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...


