Substrate recognition of tRNA (Guanosine-2'-)-methyltransferase from Thermus thermophilus HB27

Hiroyuki Hori, Norihiko Yamazaki, Takashi Matsumoto, Yo Ichi Watanabe, Takuya Ueda, Kazuya Nishikawa, Izumi Kumagai, Kimitsuna Watanabe*

*この研究の対応する著者

研究成果: Article査読

42 被引用数 (Scopus)

抄録

Transfer RNA (guanosine-2'-)-methyltransferase (Gm-methylase, EC 2.1.1.32) from Thermus thermophilus HB27 is one of the tRNA ribose modification enzymes. The broad substrate specificity of Gm-methylase has so far been elucidated using various species of tRNAs from native sources, suggesting that the common structures in tRNAs are recognized by the enzyme. In this study, by using 28 yeast tRNA(Phe) variants obtained by transcription with T7 RNA polymerase, it was revealed that the nucleotide residues G18 and G19 and the D-stem structure are essentially required for Gm-methylase recognition, and that the key sequence for the substrate is pyrimidine (Py)17G18G19. The other conserved sequences were found not to be essential, but U8, G15, G26, G46, U54, U55, and C56 considerably affected the methylation efficiency. These residues are located within a limited space embedded in the L-shaped three-dimensional structure of tRNA. Therefore, disruption of the three-dimensional structure of the substrate tRNA is necessary for the catalytic center of Gm-methylase to be able to access the target site in the tRNA, suggesting that the interaction of Gm-methylase with tRNA consists of multiple steps. This postulation was confirmed by inhibition experiments using nonsubstrate tRNA variants which functioned as competitive inhibitors against usual substrate tRNAs.

本文言語English
ページ(範囲)25721-25727
ページ数7
ジャーナルJournal of Biological Chemistry
273
40
DOI
出版ステータスPublished - 1998 10 2
外部発表はい

ASJC Scopus subject areas

  • 生化学
  • 分子生物学
  • 細胞生物学

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