由C4'-氧化基底部部位形成跨链的范围和机制
Jonathan T Sczepanski1, Aaron C Jacobs, Ananya Majumdar
1Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
Journal of the American Chemical Society
|September 3, 2009
概括
在C4'-氧化基底部部位 (C4-AP) 的DNA损伤形成了两种类型的跨链交叉链 (ICL). 序列背景显著影响ICL的形成和稳定性,可能导致细胞损伤.
科学领域:
- 在DNA损伤和修复过程中.
- 化学生物学 化学生物学 化学生物学
- 分子毒理学分子毒理学
背景情况:
- C4'-氧化基底部部位 (C4-AP) 是一个常见的DNA损伤.
- C4-AP可以导致链间交叉连接 (ICL) 的形成.
研究的目的:
- 研究C4-AP诱导的ICL形成的机制和序列依赖性.
- 描述不同ICL产品的结构和形成动力学.
主要方法:
- 使用酶消化和添加特征的DNA损伤产品的分析.
- 机理学研究,以确定ICL形成的速度限制步骤.
- 对ICL产量和稳定性的序列效应的研究.
主要成果:
- 形成了两个不同的ICL:一个具有dA的可逆动力产物和一个涉及链裂的热力学偏好的产物.
- 热力学ICL形成依赖于序列,有利于dC和da,并由当地的DNA环境催化.
- 从C4-AP中消除β是热力学ICL形成的速度限制步骤.
结论:
- 由C4-AP诱导的ICL的形成和稳定性对DNA序列环境高度敏感.
- 这些ICL,特别是热力学优势的ICL,代表生物系统中的潜在有害的DNA病变.
相关概念视频
Nucleotide Excision Repair
Overview
Long-patch Base Excision Repair
Since the discovery of the two BER pathways, there has been a debate about how a cell chooses one pathway over the other and the factors determining this selection. Numerous in vitro experiments have pointed out multiple determinants for the sub-pathway selection. These are:
Spontaneous and Induced Mutations
Spontaneous mutations arise infrequently during DNA replication due to errors in the process. A key factor behind these errors is tautomeric shifts in nitrogenous bases, where bases transition from keto to enol forms or amino to imino forms. This shift can alter base-pairing rules, leading to mutations. Additionally, reactive oxygen species (ROS) arising from aerobic metabolism can damage DNA, resulting in depurination (loss of a purine base) or depyrimidination (loss of a pyrimidine base).
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...
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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...
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...


