Samson L
Department of Molecular and Cellular Toxicology, Harvard School of Public Health, Boston, Massachusetts 02115.
Mol Microbiol. 1992 Apr;6(7):825-31. doi: 10.1111/j.1365-2958.1992.tb01533.x.
Virtually every organism so far tested has been found to possess an extremely efficient DNA repair mechanism to ensure that certain alkylated oxygens do not accumulate in the genome. The repair is executed by DNA methyltransferases (MTases) which repair DNA O6-methylguanine (O6MeG), O4-methylthymine (O4MeT) and methylphosphotriesters (MePT). The mechanism is rather extravagant because an entire protein molecule is expended for the repair of just one, or sometimes two, O-alkyl DNA adduct(s). Cells profit from such an expensive transaction by earning protection against death and mutation by alkylating agents. This review considers the structure, function and biological roles of a number of well-characterized microbial DNA repair MTases.
迄今为止，几乎所有接受测试的生物体都被发现拥有一种极其高效的DNA修复机制，以确保某些烷基化氧原子不会在基因组中积累。这种修复由DNA甲基转移酶（MTases）执行，它们修复DNA O6-甲基鸟嘌呤（O6MeG）、O4-甲基胸腺嘧啶（O4MeT）和甲基磷酸三酯（MePT）。这种机制相当奢侈，因为修复仅一个，有时是两个O-烷基DNA加合物就要消耗一整个蛋白质分子。细胞通过获得针对烷基化剂导致的死亡和突变的保护，从这种昂贵的过程中获益。本综述探讨了一些已得到充分表征的微生物DNA修复MTases的结构、功能和生物学作用。
