Enzymatic processing of radiation-induced free radical damage in DNA
Enzymatic processing of radiation-induced free radical damage in DNA
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DOI：
10.2307/3579809
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发表时间：
1998-11-01
影响因子：
3.4
通讯作者：
Wallace, SS
中科院分区：
文献类型：
--
作者：
Wallace, SS
电离辐射产生的 DNA 损伤很大一部分来自水辐射分解过程中产生的自由基，即间接效应。羟基自由基是主要的破坏性物质，会产生单链断裂和大量碱基和糖损伤，这些损伤可能具有细胞毒性或诱变性。自由基引起的 DNA 损伤通过一种称为“碱基切除修复”的高效且普遍的过程进行修复，该过程由三个或四个酶促步骤组成，具体取决于最初的损伤。结果是修复补丁尺寸较短的完整 DNA 分子。然而，如果通过碱基切除修复来处理与电离辐射产生的类似的多重损伤位点，则如果相反的损伤相距超过三个核苷酸，则可能导致双链断裂。由于碱基切除修复的进化是为了保护基因组免受内源性损伤，因此所涉及的蛋白质从细菌到人类都高度保守，不仅在功能水平上，而且在氨基酸序列水平上。 (C) 1998 年，辐射研究会。
A significant fraction of DNA damage produced by ionizing radiation comes from free radicals generated during the radiolysis of water, that is, by indirect effects. The hydroxyl radical, the principal damaging species, produces single-strand breaks and a plethora of base and sugar lesions that can be cytotoxic or mutagenic. Free radical-induced DNA damage is repaired by an efficient and ubiquitous process called "base excision repair" which is composed of either three or four enzymatic steps, depending on the initial lesion. The result is an intact DNA molecule with a short repair patch size. If, however, multiply damaged sites similar to those produced by ionizing radiation are processed by base excision repair, a double-strand break can result if the opposing lesions are more than three nucleotides apart. Because base excision repair evolved to protect the genome from endogenous damages, the proteins involved are highly conserved from bacteria to humans, not only at the functional level, but at the level of amino acid sequence. (C) 1998 by Radiation Research Society.