Téoule R
Int J Radiat Biol Relat Stud Phys Chem Med. 1987 Apr;51(4):573-89. doi: 10.1080/09553008414552111.
Application of modern methods of organic chemistry and recombinant DNA technologies has provided new insights in the field of DNA radiation damage and its repair. An overview of the chemical nature of the lesions inflicted on DNA by ionizing radiation is presented. The structures of 29 different DNA modified base or sugar residues are shown in comprehensive formation schemes. A fraction of radiation-induced modified bases is spontaneously released from the DNA chain during irradiation. Another part remains attached to the DNA chain backbone and for its characterization mild formic acid or enzymatic hydrolysis have been used. Starting from the chemical formulae of the altered base residues, the specific repair enzymes and their modes of action are discussed. Various glycosylases and endonucleases have been purified to homogeneity, and in some cases the gene which encodes the protein cloned. Using methods derived from Maxam and Gilbert sequencing procedures and DNA fragment 32P-labelled at one end, it has been shown that the alkali-labile sites in DNA induced by radiation are strongly dependent on the DNA base sequence. Enzymatic methods have been used to analyse the DNA base defects produced by gamma-irradiation of cells under in vivo conditions. Structures of modified bases were the same as those observed when DNA was irradiated in aqueous solution.
现代有机化学方法和重组DNA技术的应用为DNA辐射损伤及其修复领域提供了新的见解。本文概述了电离辐射对DNA造成的损伤的化学性质。29种不同的DNA修饰碱基或糖残基的结构在全面的形成方案中展示。一部分辐射诱导的修饰碱基在辐照过程中会从DNA链上自发释放。另一部分则仍附着在DNA链主链上，为了对其进行表征，人们使用了温和的甲酸或酶促水解方法。从改变后的碱基残基的化学式出发，讨论了特定的修复酶及其作用方式。多种糖基化酶和核酸内切酶已被纯化至同质，在某些情况下，编码该蛋白质的基因也已被克隆。利用源自马克萨姆和吉尔伯特测序程序的方法以及一端用32P标记的DNA片段，已表明辐射诱导的DNA中的碱不稳定位点强烈依赖于DNA碱基序列。酶促方法已被用于分析体内条件下细胞经γ射线照射后产生的DNA碱基缺陷。修饰碱基的结构与在水溶液中照射DNA时观察到的结构相同。
