...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of bacteriology >A Novel Role for Escherichia coliEndonuclease VIII in Prevention of Spontaneous G→T Transversions
【24h】

A Novel Role for Escherichia coliEndonuclease VIII in Prevention of Spontaneous G→T Transversions

机译：大肠杆菌内切酶VIII在预防自发G→T转化中的新作用

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In the bacterium Escherichia coli, oxidized pyrimidines are removed by two DNA glycosylases, endonuclease III and endonuclease VIII (endo VIII), encoded by the nth and neigenes, respectively. Double mutants lacking both of these activities exhibit a high spontaneous mutation frequency, and here we show that all of the mutations observed in the double mutants were G:C→A:T transitions; no thymine mutations were found. These findings are in agreement with the preponderance of C→T transitions in the oxidative and spontaneous mutational databases. The major oxidized purine lesion in DNA, 7,8-dihydro-8-oxoguanine (8-oxoG), is processed by two DNA glycosylases, formamidopyrimidine DNA glycosylase (Fpg), which removes 8-oxoG opposite C, and MutY DNA glycosylase, which removes misincorporated A opposite 8-oxoG. The high spontaneous mutation frequency previously observed in fpg mutY double mutants was significantly enhanced by the addition of the neimutation, suggesting an overlap in the substrate specificities between endo VIII and Fpg/MutY. When the mutational specificity was examined, all of the mutations observed were G:C→T:A transversions, indicating that in the absence of Fpg and MutY, endo VIII serves as a backup activity to remove 8-oxoG. This was confirmed by showing that, indeed, endo VIII can recognize 8-oxoG in vitro.
机译：在细菌大肠杆菌中，氧化的嘧啶被两种DNA糖基化酶（内切酶III和内切酶VIII（内切VIII））去除，这两种酶由 n 和 nei编码。 em> genes。缺乏这两种活性的双突变体表现出很高的自发突变频率，在这里我们表明在双突变体中观察到的所有突变都是G：C→A：T转变。没有发现胸腺嘧啶突变。这些发现与氧化和自发突变数据库中的C→T跃迁相一致。 DNA中的主要氧化嘌呤病变7,8-dihydro-8-oxoguanine（8-oxoG）由两种DNA糖基化酶处理，即甲酰嘧啶DNA糖基化酶（Fpg），可去除与C相反的8-oxoG和MutY DNA糖基化酶，去除错误掺入的A相对的8-oxoG。以前在 fpg mutY 双重突变体中观察到的高自发突变频率通过添加 nei 突变而得到显着增强，这表明内在VIII和Fpg /之间的底物特异性重叠。互斥。当检查突变特异性时，观察到的所有突变都是G：C→T：A转化，表明在没有Fpg和MutY的情况下，内膜VIII充当去除8-oxoG的后备活性。通过证明实际上，内在VIII可以在体外识别8-oxoG来证实这一点。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号