論文

2013年8月

The Catalytic Domain of Topological Knot tRNA Methyltransferase (TrmH) Discriminates between Substrate tRNA and Nonsubstrate tRNA via an Induced-fit Process

JOURNAL OF BIOLOGICAL CHEMISTRY
  • Anna Ochi
  • ,
  • Koki Makabe
  • ,
  • Ryota Yamagami
  • ,
  • Akira Hirata
  • ,
  • Reiko Sakaguchi
  • ,
  • Ya-Ming Hou
  • ,
  • Kazunori Watanabe
  • ,
  • Osamu Nureki
  • ,
  • Kunihiro Kuwajima
  • ,
  • Hiroyuki Hori

288
35
開始ページ
25562
終了ページ
25574
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1074/jbc.M113.485128
出版者・発行元
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

A conserved guanosine at position 18 (G18) in the D-loop of tRNAs is often modified to 2'-O-methylguanosine (Gm). Formation of Gm18 in eubacterial tRNA is catalyzed by tRNA (Gm18) methyltransferase (TrmH). TrmH enzymes can be divided into two types based on their substrate tRNA specificity. Type I TrmH, including Thermus thermophilus TrmH, can modify all tRNA species, whereas type II TrmH, for example Escherichia coli TrmH, modifies only a subset of tRNA species. Our previous crystal study showed that T. thermophilus TrmH is a class IV S-adenosyl-L-methionine-dependent methyltransferase, which maintains a topological knot structure in the catalytic domain. Because TrmH enzymes have short stretches at the N and C termini instead of a clear RNA binding domain, these stretches are believed to be involved in tRNA recognition. In this study, we demonstrate by site-directed mutagenesis that both N-and C-terminal regions function in tRNA binding. However, in vitro and in vivo chimera protein studies, in which four chimeric proteins of type I and II TrmHs were used, demonstrated that the catalytic domain discriminates substrate tRNAs from nonsubstrate tRNAs. Thus, the N- and C-terminal regions do not function in the substrate tRNA discrimination process. Pre-steady state analysis of complex formation between mutant TrmH proteins and tRNA by stopped-flow fluorescence measurement revealed that the C-terminal region works in the initial binding process, in which nonsubstrate tRNA is not excluded, and that structural movement of the motif 2 region of the catalytic domain in an induced-fit process is involved in substrate tRNA discrimination.

Web of Science ® 被引用回数 : 23

リンク情報
DOI
https://doi.org/10.1074/jbc.M113.485128
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000330619000051&DestApp=WOS_CPL

エクスポート
BibTeX RIS