The spoU gene of Escherichia coli, the fourth gene of the spoT operon, is essential for tRNA (Gm18) 2'-O-methyltransferase activity
The spoU gene of Escherichia coli, the fourth gene of the spoT operon, is essential for tRNA (Gm18) 2'-O-methyltransferase activity
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DOI：
10.1093/nar/25.20.4093
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发表时间：
1997-10-15
影响因子：
14.9
通讯作者：
Gustafsson, C
中科院分区：
文献类型：
--
作者：
Persson, BC;Jager, G;Gustafsson, C
我们有证据表明，开放阅读框先前表示的spoU是tRNA (Gm18) 2'- o -甲基转移酶活性所必需的。spoU基因位于大肠杆菌染色体上的gmk-rpoZ-spoT-spoU-recG操纵子82分钟处，推断出的spoU氨基酸序列与先前表征的2'- o -甲基转移酶具有很强的相似性。比较野生型和spoU零突变体的水解tRNA、16S rRNA和23S rRNA的核苷修饰模式发现，在大肠杆菌tRNA残基18亚群中存在的修饰核苷2′- o -甲基鸟苷（Gm）在spoU突变体中完全不存在，这表明spoU编码tRNA (Gm18) 2′- o -甲基转移酶。在spoU突变体中，16S和23S rRNA的核苷修饰不受影响，下游recG基因的插入不影响RNA修饰，tRNA中Gm18的缺失不影响测试条件下的生长速度，也不干扰SupF amber抑制因子的活性，而SupF amber抑制因子通常具有Gm18修饰，我们建议将spoU基因更名为trmH （tRNA甲基化）。
We have evidence that the open reading frame previously denoted spoU is necessary for tRNA (Gm18) 2'-O-methyltransferase activity. The spoU gene is located in the gmk-rpoZ-spoT-spoU-recG operon at 82 minutes on the Escherichia coli chromosome, The deduced amino acid sequence of spoU shows strong similarities to previously characterized 2'-O-methyltransferases. Comparison of the nucleoside modification pattern of hydrolyzed tRNA, 16S rRNA and 23S rRNA from wild-type and spoU null mutants showed that the modified nucleoside 2'-O-methylguanosine (Gm), present in a subset of E.coli tRNAs at residue 18, is completely absent in the spoU mutant, suggesting that spoU encodes tRNA (Gm18) 2'-O-methyltransferase. Nucleoside modification of 16S and 23S rRNA was unaffected in the spoU mutant, Insertions in the downstream recG gene did not affect RNA modification, Absence of Gm18 in tRNA does not influence growth rate under the tested conditions and does not interfere with activity of the SupF amber suppressor, a suppressor tRNA that normally has the Gm18 modification, We suggest that the spoU gene be renamed trmH (tRNA methylation).