KsgA, a 16S rRNA adenine methyltransferase, has a novel DNA glycosylase/AP lyase activity to prevent mutations in Escherichia coli.
KsgA, a 16S rRNA adenine methyltransferase, has a novel DNA glycosylase/AP lyase activity to prevent mutations in Escherichia coli.
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DOI：
10.1093/nar/gkp057
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发表时间：
2009-04
影响因子：
14.9
通讯作者：
Yonei S
中科院分区：
文献类型：
--
作者：
Zhang-Akiyama QM;Morinaga H;Kikuchi M;Yonekura S;Sugiyama H;Yamamoto K;Yonei S
5-甲酰尿嘧啶（5-foU）是胸腺嘧啶的主要致突变氧化损伤，在大肠杆菌中被Nth、Nei和MutM从DNA中去除。然而，DNA聚合酶也可以复制过去的5-foU通过纳入C和G对面的病变，虽然机制的纠正纳入基地仍然是未知的。在这项研究中，使用硼氢化物捕获试验，我们确定了一个蛋白质捕获的5-foU/C-含有寡核苷酸的提取物中的E。大肠杆菌mutM nth nei突变体。随后从E. coli mutM nth nei突变株，经鉴定为KsgA，是一种16 S rRNA腺嘌呤甲基转移酶。重组KsgA还与含5-foU/C-和胸腺嘧啶乙二醇（Tg）/C的寡核苷酸形成捕获复合物。此外，KsgA通过β-消除反应从双链体寡核苷酸中切除与5-foU、Tg和5-羟甲基尿嘧啶（5-hmU）相对的C，而它不能去除受损的碱基。相比之下，KsgA不去除C对正常碱基，7，8-二氢-8-氧代鸟嘌呤和2-羟基腺嘌呤。最后，引入ksgA突变增加了E. coli mutM mutY和nth nei突变体。这些结果表明，KsgA具有一种新的DNA糖基化酶/AP裂解酶活性的C错配与氧化的T，防止形成突变，这是除了其已知的rRNA腺嘌呤甲基转移酶活性的核糖体生物合成所必需的。
The 5-formyluracil (5-foU), a major mutagenic oxidative damage of thymine, is removed from DNA by Nth, Nei and MutM in Escherichia coli. However, DNA polymerases can also replicate past the 5-foU by incorporating C and G opposite the lesion, although the mechanism of correction of the incorporated bases is still unknown. In this study, using a borohydride-trapping assay, we identified a protein trapped by a 5-foU/C-containing oligonucleotide in an extract from E. coli mutM nth nei mutant. The protein was subsequently purified from the E. coli mutM nth nei mutant and was identified as KsgA, a 16S rRNA adenine methyltransferase. Recombinant KsgA also formed the trapped complex with 5-foU/C- and thymine glycol (Tg)/C-containing oligonucleotides. Furthermore, KsgA excised C opposite 5-foU, Tg and 5-hydroxymethyluracil (5-hmU) from duplex oligonucleotides via a β-elimination reaction, whereas it could not remove the damaged base. In contrast, KsgA did not remove C opposite normal bases, 7,8-dihydro-8-oxoguanine and 2-hydroxyadenine. Finally, the introduction of the ksgA mutation increased spontaneous mutations in E. coli mutM mutY and nth nei mutants. These results demonstrate that KsgA has a novel DNA glycosylase/AP lyase activity for C mispaired with oxidized T that prevents the formation of mutations, which is in addition to its known rRNA adenine methyltransferase activity essential for ribosome biogenesis.
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DOI：
10.1038/newbio233012a0
发表时间：
1971-01-01
期刊：
NATURE-NEW BIOLOGY
影响因子：
--
作者：
HELSER, TL;DAVIES, JE;DAHLBERG, JE
通讯作者：
DAHLBERG, JE
DOI：
10.1016/j.mrfmmm.2003.07.002
发表时间：
2003-10-29
影响因子：
2.3
作者：
Bjelland, S;Seeberg, E
通讯作者：
Seeberg, E
影响因子：
3.8
作者：
Hazra, Tapas K.;Das, Aditi;Roy, Rabindra
通讯作者：
Roy, Rabindra
DOI：
10.1073/pnas.89.15.7022
发表时间：
1992-08-01
影响因子：
11.1
作者：
MICHAELS, ML;CRUZ, C;MILLER, JH
通讯作者：
MILLER, JH
影响因子：
3.2
作者：
BOCHNER, BR;HUANG, HC;AMES, BN
通讯作者：
AMES, BN