O6-methylguanine-DNA methyltransferase in wild-type and ada mutants of Escherichia coli
O6-methylguanine-DNA methyltransferase in wild-type and ada mutants of Escherichia coli
复制标题
野生型和 ada 突变型大肠杆菌中的 O6-甲基鸟嘌呤-DNA 甲基转移酶
DOI：
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发表时间：
1982
影响因子：
3.2
通讯作者：
Robert S. Foote
中科院分区：
文献类型：
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作者：
Sankar Mitra;B. C. Pal;Robert S. Foote
大肠杆菌在低浓度N-甲基-N '-硝基-N-亚硝基胍中生长时，O（6）-甲基鸟嘌呤-DNA甲基转移酶被诱导。我们已经开发了一种灵敏的测定定量低水平的这种活动与合成的DNA底物含有3 H-标记的O（6）-甲基鸟嘌呤作为唯一的修改基地。虽然野生型和适应缺陷型突变体E.大肠杆菌中每个细胞含有的酶分子数低但相当（从13到60），适应处理引起野生型中的酶的显著增加，但在ADA突变体中没有，这表明ADA突变位于调节位点，而不是甲基转移酶的结构基因。
O(6)-Methylguanine-DNA methyltransferase is induced in Escherichia coli during growth in low levels of N-methyl-N'-nitro-N-nitrosoguanidine. We have developed a sensitive assay for quantitating low levels of this activity with a synthetic DNA substrate containing 3H-labeled O(6)-methylguanine as the only modified base. Although both wild-type and adaptation-deficient (ada) mutants of E. coli contained low but comparable numbers (from 13 to 60) of the enzyme molecules per cell, adaptation treatment caused a significant increase of the enzyme in the wild type but not in the ada mutants, suggesting that the ada mutation is in a regulatory locus and not in the structural gene for the methyltransferase.