概括
核体的外核酶III (Exo III) 消化揭示了一个精确的140bp核心. 进一步的消化产生长度为10个基间隔的DNA片段,表明结构特征指导了酶.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 结构生物学 结构生物学
背景情况:
- 细胞核是真核生物中DNA包装的基本单元.
- 了解核体结构和DNA可访问性对于基因调节至关重要.
研究的目的:
- 为了研究Exonuclease III (Exo III) 在核体上的核酶活性.
- 为了表征由核子体的 Exo III 消化产生的 DNA 片段.
主要方法:
- 通过增加大肠杆菌外核酶III度对核体进行处理.
- 通过酶性消化产生的DNA片段大小的分析.
主要成果:
- 低Exo III度将异质核素单体切割到一个离散的140bp核心.
- 较高的Exo III度会消化140bp的核心,产生长度为10个基数间隔的碎片.
- 埃克索III可以从二元核体中消化大量的DNA长度,保持10个基阶梯模式.
结论:
- 埃克索III在核细胞上表现出3'外核解和5'剪切活动.
- 核酶体结构决定了Exo III消化模式,产生离散的DNA片段长度.
- 酶保持10个基梯的能力表明它可以导航核细胞架构.
相关概念视频
Nucleotide Excision Repair
Overview
Base Excision Repair
One of the common DNA damages is the chemical alteration of single bases by alkylation, oxidation, or deamination. The altered bases cause mispairing and strand breakage during replication. This type of damage causes minimal change to the DNA double helix structure and can be repaired by the base excision repair (BER) pathways. BER corrects damaged DNA sequences by removing the damaged base and restoring the original base sequence using the complementary strand as a template.
The first step of...
The first step of...
Nucleotide Excision Repair
Overview
Homologous Recombination
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
Base Excision Repair
One of the common DNA damages is the chemical alteration of single bases by alkylation, oxidation, or deamination. The altered bases cause mispairing and strand breakage during replication. This type of damage causes minimal change to the DNA double helix structure and can be repaired by the base excision repair (BER) pathways. BER corrects damaged DNA sequences by removing the damaged base and restoring the original base sequence using the complementary strand as a template.
The first step of...
The first step of...
Nucleotide Excision Repair
DNA Distortion and Damage
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...


