相关实验视频
Updated: Jan 9, 2026
01:19
Regulation of Hormone Secretion
6.0K
在T. aquaticus的DNA聚合酶III的结构不同于真核生物的复制DNA聚合酶
Scott Bailey1, Richard A Wing, Thomas A Steitz
1Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
Cell
|September 9, 2006
概括
热水族DNA聚合酶III的晶体结构显示其催化域与真核聚合酶无关,而是属于类似Polbeta的超级家族. 一个结构模型解释了DNA和β-滑动的相互作用,与生物化学数据一致.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 分子生物学分子生物学
背景情况:
- 欧细菌和真核生物复制性DNA聚合酶共享功能作用,但表现出结构上的差异.
- 了解DNA聚合酶的进化起源和结构关系对于破译基本的生物过程至关重要.
研究的目的:
- 为了确定Thermus aquaticus DNA聚合酶IIIα子单元的晶体结构.
- 阐明DNA和β滑动相互作用的结构基础.
- 研究细菌复制聚合酶的进化关系.
主要方法:
- 采用X射线晶体学,确定了Thermus aquaticus DNA聚合酶IIIα子单元的高分辨率晶体结构.
- 计算机建模被用来构建一个聚合酶与DNA复合的模型和β滑动.
主要成果:
- 热水族DNA聚合酶III的催化域在结构上与真核生物复制聚合酶不同,属于类似Polbeta的核基转移酶超级家族.
- 一个结构模型准确地描述了聚合酶与DNA和β滑动的相互作用,与现有的生化证据保持一致.
- C端域表现出广泛的相互作用,形成一个大的二进制接口.
结论:
- 超细菌的复制DNA聚合酶与它们的真核生物和古生物对应物不相同,使得最后一个共同祖先中的复制聚合酶的性质不确定.
- 这些发现表明,在DNA聚合酶的早期历史中存在潜在的进化分歧.
- 在早期生命形式中可能存在 ribozyme DNA 聚合酶的可能性值得考虑.
相关概念视频
Regulation of Hormone Secretion
6.0K
Regulation of hormone secretion is a finely tuned orchestration driven by various types of stimuli, encompassing neural, humoral, and hormonal signals. Environmental cues instigate neural stimuli, where action potentials traverse nerve fibers to reach their designated targets. An illustrative scenario is the body's response to stress, wherein the sympathetic nervous system releases epinephrine from the adrenal glands, inducing the well-known 'fight or flight' reaction.
Humoral...
Humoral...
6.0K
Hormonal Regulation
47.7K
Hormones regulate a significant portion of digestion through activation of the neuroendocrine system. The neuroendocrine system of digestion contains many different hormones all with multiple functions that are both, directly and indirectly, involved in digestion.
47.7K
Overview of Secretory Vesicles
9.3K
Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
9.3K
Insulin Secretory Vesicles
6.3K
Insulin secretory vesicles release insulin to stimulate blood glucose uptake and regulate carbohydrate metabolism. When the blood glucose levels increase, glucose enters the pancreatic β-islet cells through glucose transporters. Once inside, glucose is metabolized through glycolysis, the citric acid cycle, and the electron transport chain, producing ATP. This increase in ATP concentration closes ATP-sensitive potassium channels, leading to depolarization of the membrane and the opening of...
6.3K
Glucose Homeostasis: Pancreatic Islets and Insulin Secretion
2.1K
The pancreatic islets comprising only 1%-2% of the volume are highly vascularized and innervated mini-organs. They contain five endocrine cell types, including β cells that secrete insulin, which is synthesized as a single polypeptide chain, preproinsulin, processed to proinsulin, and finally to insulin and C-peptide. This process is complex and regulated, involving the Golgi complex, the endoplasmic reticulum, and the secretory granules of the β cell.
Insulin and C-peptide are...
Insulin and C-peptide are...
2.1K
Feedback Inhibition
56.8K
Biochemical reactions are occurring constantly in cells, converting starting substances to different products, usually with the help of enzymes that speed the reactions. Without enzymes, it would take far too long for most reactions to occur to be useful to the cell!
56.8K