Interaction of metronidazole with Escherichia coli deoxyribonucleic acid.
Interaction of metronidazole with Escherichia coli deoxyribonucleic acid.
复制标题
甲硝唑与大肠杆菌脱氧核糖核酸的相互作用。
DOI：
10.1016/0006-2952(91)90510-c
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发表时间：
1991
影响因子：
5.8
通讯作者：
Goldman,P
中科院分区：
文献类型：
--
作者：
Malliaros,DP;Goldman,P
为了确定已报道的甲硝唑与 DNA 结合的特征，我们从含有 [14C]甲硝唑和甲硝唑敏感大肠杆菌菌株的低氧培养混合物中分离出 DNA。因此，将[2-14C]甲硝唑或[1',2'-14C]甲硝唑与野生型大肠杆菌（菌株AB1157）或对甲硝唑高度敏感的DNA修复突变体（菌株SR58）一起温育。发现甲硝唑中大约 0.02% 的放射性标记与从两种细菌菌株中分离出的 DNA 相关，该百分比与其他研究人员进行的各种体外和体内实验中发现的与哺乳动物来源的 DNA 相关的百分比相似。然而，当孵育混合物中包含大量过量的非放射性标记的甲硝唑时，结合的放射性并没有减弱，这表明我们观察到的结合可能是由于放射性标记的甲硝唑中的杂质造成的。我们还检查了甲硝唑部分还原形式的可能替代物 1-甲基-4-苯基-5-亚硝基咪唑 (5NO) 与 DNA 的结合，这已在前面描述过。还发现，添加载体 5NO 不会减弱氚化形式的 5NO 与 DNA 的结合（这一发现并没有反驳 5NO 可以作为甲硝唑活性形式研究的替代物的假设）。这些研究并不排除甲硝唑或其活性功能的可能替代物与 DNA 的结合，但它们表明，如果发生这种结合，它必须仅限于 DNA 上的极少数位点，因此难以表征。
To define the characteristics of the reported binding of metronidazole to DNA, we isolated the DNA from hypoxic incubation mixtures that contained both [14C]metronidazole and metronidazolesusceptible strains ofEscherichia coli. Thus, either [2-14C] metronidazole or [1',2'-14C] metronidazole was incubated with either wild-typeE.coli(strain AB1157) or a DNA repair mutant (strain SR58) that is highly susceptible to metronidazole. Approximately 0.02% of the radiolabel in the metronidazole was found to be associated with DNA isolated from both strains of bacteria, a percentage similar to that found to be associated with DNA from mammalian sources in a variety ofin vitroandin vivoexperiments performed by other investigators. The bound radioactivity was not diminished, however, when a great excess of non-radiolabeled metronidazole was included in the incubation mixture, indicating that the binding we observed was probably due to impurities in the radiolabeled metronidazole. We also examined the binding to DNA of a possible surrogate for the partially reduced form of metronidazole, l-methyl-4-phenyl-5-nitrosoimidazole (5NO), that has been described previously. The binding of the tritiated form of 5NO to DNA was also found to be undiminished by the addition of carrier 5NO (a finding which does not refute the hypothesis that 5NO may serve as a surrogate for the study of the active form of metronidazole). These studies do not exclude the binding to DNA of either metronidazole or a possible surrogate of its active functionality, but they indicate that if such binding occurs, it must be limited to very few sites on DNA and hence will be difficult to characterize.