相关实验视频
Updated: Jun 10, 2025

11:27
Studying DNA Looping by Single-Molecule FRET
Published on: June 28, 2014
15.4K
内部和突起环对小DNA复合体的热稳定性的影响
Earle Stellwagen1, Paul J Barnard1,2, Nancy C Stellwagen1
1Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, United States.
The journal of physical chemistry. B
|October 15, 2024
概括
用毛细管电泳分析研究了DNA双重体的热稳定性. DNA中的环结构影响稳定性和链分离,特定的离子有助于完全分离.
科学领域:
- 分子生物学分子生物学
- 生物物理学的生物物理.
- 生物化学 生物化学
背景情况:
- 这种let-7微RNA:lin-41mRNA复合体对于Caenorhabditis elegans的基因调节至关重要.
- 了解核酸相互作用的生物物理特性对于分子生物学和药物开发至关重要.
研究的目的:
- 为了研究模仿let-7:lin-41复合体的DNA复合体的热稳定性.
- 分析内部和膨胀循环对DNA双重稳定性和变性动态的影响.
- 探索实现DNA复合体与其构成单个链完全分离的方法.
主要方法:
- 使用自由溶液毛细管电泳来测量各种DNA复合体的热稳定性.
- 在一系列的 (Na+) 和 (K+) 离子度中确定了化温度.
- 使用电电图峰值分析来评估双重变性和线程分离.
主要成果:
- DNA双重融温度与Na+或K+离子度的对数线性增加.
- 带有内部或膨胀环的复式显示在高温下显著的峰值尾部,表明缓慢的变性.
- 在20°C的温度下,在300毫米米的四胺离子溶液中,从单个链中完全分离双重链.
- 发现内部或膨胀循环可以减少DNA复杂体中的 counterion 凝结.
结论:
- 内部和膨胀环影响DNA双重体的热稳定性和变性机制.
- 特定的离子条件,特别是四烯离子,可以促进完全的双重单链分离.
- 这些发现为与基因调节相关的核酸复合物的生物物理行为提供了洞察力.
相关概念视频
Single-Strand DNA Binding Proteins
14.0K
For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...
14.0K
DNA Topoisomerases
31.0K
Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types. ...
Types and Mechanism of action
Topoisomerases are divided into two main types. ...
31.0K
Fixing Double-strand Breaks
12.5K
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
12.5K
The DNA Replication Fork
35.6K
An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork. Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication...
35.6K
Overview of DNA Repair
30.7K
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
Chemically...
30.7K
DNA as a Genetic Template
21.8K
Two structural features of the DNA molecule provide a basis for the mechanisms of heredity: the four nucleotide bases and its double-stranded nature. The Watson-Crick model of double-helical DNA structure, proposed in 1952, drew heavily upon the X-ray crystallography work of researchers Rosalind Franklin and Maurice Wilkins. Watson, Crick, and Wilkins jointly received the Nobel Prize in Physiology or Medicine for their work in 1962. Franklin was, controversially, excluded from the prize for...
21.8K

