由 peracids 和其他氧化氧化剂诱导的 DNA 中的 iminohydantoin 损伤
Wenjie Ye1, R Sangaiah, Diana E Degen
1Department of Environmental Sciences and Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Journal of the American Chemical Society
|April 10, 2009
概括
一个新的DNA损伤,5-carboxamido-5-formamido-2-iminohydantoin (2-Ih),是由 peracids 的瓜氧化形成的. 这种稳定的2-I损伤可以作为潜在的体内生物标志物.
科学领域:
- 氧化应激和DNA损伤
- 化学致癌和突变发生.
- 发现生物标志物的发现.
背景情况:
- 关氨酸容易受到氧化损伤,形成各种病变.
- 像m-二酸 (m-CPBA) 和二甲基二氧化 (DMDO) 这样的甲酸是研究DNA损伤的模型氧化剂.
- 这些药物在DNA中对瓜的氧化转化还没有完全被阐明.
研究的目的:
- 为了识别和表征由 peracids 在 DNA 中形成的氧化病变.
- 通过m-CPBA和DMDO研究瓜氧化机制.
- 评估新型氧化病变作为生物标志物的潜力.
主要方法:
- 使用m-CPBA和DMDO的单链DNA (5-mer) 和双链DNA (5-基对双重) 的氧化.
- 单质瓜核酸和核酸 (dGuo,dGMP,dGTP) 的氧化,以探测反应机制.
- 使用先进的分析技术对氧化产品进行结构性表征.
- 用[{18) O{2}-m-CPBA和H{2}{18) O进行同位素标记研究,以追踪氧原子的起源.
主要成果:
- 在DNA中形成5-carboxamido-5-formamido-2-iminohydantoin (2-Ih) 作为主要的瓜氧化产物.
- 2-Ih是一种新型的氧化损伤,以前没有在DNA,核酸或核酸中报告过.
- 病变对DNA消化和色谱净化是稳定的.
- 机理学研究显示,关氨酸4-5键的初始环氧化,随后环收缩和开放.
- 没有检测到8-oxoguanine,这表明了特定途径的病变形成.
结论:
- peracids 和潜在的其他环氧化剂会产生新型的 2-Ih 关氨酸损伤.
- 2-Ih的稳定性表明它有可能成为氧化损伤的可靠体内生物标志物.
- 了解这种特定的氧化途径可以了解DNA损伤和修复机制.
相关概念视频
Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
Nucleotide Excision Repair
Overview
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...
Nucleotide Excision Repair
Overview
Overview of DNA Repair
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...
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).


