概括
T4内核酶VII分裂霍莱德结构,分解DNA复制中间体. 它与DNA结合酶的作用产生了基因敏感的产物,澄清了它在菌体T4DNA代谢中的作用.
科学领域:
- 分子生物学分子生物学
- 酶学 是一种酶学.
- 在DNA复制和修复过程中,
背景情况:
- 霍利代结构是DNA重组和修复中的关键中间体.
- T4内核酶VII参与菌体T4的DNA代谢.
研究的目的:
- 阐明T4内核酶VII分解霍莱德结构的机制.
- 了解T4内核酶VII在产生基因敏感DNA产品中的作用.
主要方法:
- 在试验室中使用纯化的T4内核酶VII进行切割试验.
- 通过内核酶VII活动产生的DNA产品的分析.
主要成果:
- T4内核酶VII特别在分支点或附近切割霍莱德结构的两个链.
- 裂变会产生两个未分支的DNA复合体,每一个都有单链断裂.
- 链断裂发生在每个链上的核酸序列内的相同位置.
结论:
- T4内核酶VII作用于双重DNA的分支点,解决霍莱德结构.
- T4内核酶VII和DNA结合酶的联合作用可以修复链断裂,产生功能性DNA.
- 这些发现解释了该酶在菌体T4DNA代谢中的功能,并将其确定为第一个具有特定分支点活性的酶.
相关概念视频
Nucleotide Excision Repair
Overview
Nucleotide Excision Repair
Overview
Translesion DNA Polymerases
Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
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...
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...
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...


