Sergiev Petr V, Bogdanov Alexey A, Dontsova Olga A
Department of Chemistry and A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.
Nucleic Acids Res. 2007;35(7):2295-301. doi: 10.1093/nar/gkm104. Epub 2007 Mar 27.
Five nearly universal methylated guanine-(N2) residues are present in bacterial rRNA in the ribosome. To date four out of five ribosomal RNA guanine-(N2)-methyltransferases are described. RsmC(YjjT) methylates G1207 of the 16S rRNA. RlmG(YgjO) and RlmL(YcbY) are responsible for the 23S rRNA m(2)G1835 and m(2)G2445 formation, correspondingly. RsmD(YhhF) is necessary for methylation of G966 residue of 16S rRNA. Structure of Escherichia coli RsmD(YhhF) methyltransferase and the structure of the Methanococcus jannaschii RsmC ortholog were determined. All ribosomal guanine-(N2)-methyltransferases have similar AdoMet-binding sites. In relation to the ribosomal substrate recognition, two enzymes that recognize assembled subunits are relatively small single domain proteins and two enzymes that recognize naked rRNA are larger proteins containing separate methyltransferase- and RNA-binding domains. The model for recognition of specific target nucleotide is proposed. The hypothetical role of the m(2)G residues in rRNA is discussed.
核糖体中的细菌rRNA存在五个几乎普遍存在的甲基化鸟嘌呤 - （N2）残基。迄今为止，已描述了五种核糖体RNA鸟嘌呤 - （N2） - 甲基转移酶中的四种。RsmC（YjjT）使16S rRNA的G1207甲基化。RlmG（YgjO）和RlmL（YcbY）分别负责23S rRNA的m（2）G1835和m（2）G2445的形成。RsmD（YhhF）是16S rRNA的G966残基甲基化所必需的。已确定大肠杆菌RsmD（YhhF）甲基转移酶的结构以及詹氏甲烷球菌RsmC直系同源物的结构。所有核糖体鸟嘌呤 - （N2） - 甲基转移酶都具有相似的腺苷甲硫氨酸结合位点。关于核糖体底物识别，识别组装亚基的两种酶是相对较小的单结构域蛋白，而识别裸露rRNA的两种酶是含有单独的甲基转移酶和RNA结合结构域的较大蛋白。提出了识别特定靶核苷酸的模型。讨论了rRNA中m（2）G残基的假设作用。
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