HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 279, Issue 47, 49151-49159, November 19, 2004

This Article Full Text Full Text (PDF) All Versions of this Article: 279/47/49151    most recent M408209200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Okamoto, H. Articles by Hori, H. Search for Related Content PubMed PubMed Citation Articles by Okamoto, H. Articles by Hori, H. Social Bookmarking                      What's this?

Substrate tRNA Recognition Mechanism of tRNA (m⁷G46) Methyltransferase from Aquifex aeolicus^*

Hironori Okamoto, Kazunori Watanabe, Yoshiho Ikeuchi, Tsutomu Suzuki, Yaeta Endo¶||, and Hiroyuki Hori¶**

From the Department of Applied Chemistry, Faculty of Engineering, Ehime University, Bunkyo 3, Matsuyama, 790-8577, Japan, Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8562, Japan, ^¶Venture Business Laboratory, Ehime University, Bunkyo 3, Matsuyama, 790-8577, Japan, and ^||Cell-free Science and Technology Research Center, Ehime University, Matsuyama, 790-8577, Japan

Transfer RNA (m⁷G46) methyltransferase catalyzes the methyl transfer from S-adenosylmethionine to N⁷ atom of the guanine 46 residue in tRNA. Analysis of the Aquifex aeolicus genome revealed one candidate open reading frame, aq065, encoding this gene. The aq065 protein was expressed in Escherichia coli and purified to homogeneity on 15% SDS-polyacrylamide gel electrophoresis. Although the overall amino acid sequence of the aq065 protein differs considerably from that of E. coli YggH, the purified aq065 protein possessed a tRNA (m⁷G46) methyltransferase activity. The modified nucleoside and its location were determined by liquid chromatography-mass spectroscopy. To clarify the RNA recognition mechanism of the enzyme, we investigated the methyl transfer activity to 28 variants of yeast tRNA^Phe and E. coli tRNA^Thr. It was confirmed that 5'-leader and 3'-trailer RNAs of tRNA precursor are not required for the methyl transfer. We found that the enzyme specificity was critically dependent on the size of the variable loop. Experiments using truncated variants showed that the variable loop sequence inserted between two stems is recognized as a substrate, and the most important recognition site is contained within the T stem. These results indicate that the L-shaped tRNA structure is not required for methyl acceptance activity. It was also found that nucleotide substitutions around G46 in three-dimensional core decrease the activity.

Received for publication, July 20, 2004 , and in revised form, August 30, 2004.

^* The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

^** To whom correspondence should be addressed. Tel.: 81-89-927-8548; Fax: 81-89-927-9941; E-mail: hori{at}eng.ehime-u.ac.jp.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				H. Nishimasu, R. Ishitani, K. Yamashita, C. Iwashita, A. Hirata, H. Hori, and O. Nureki Atomic structure of a folate/FAD-dependent tRNA T54 methyltransferase PNAS, May 19, 2009; 106(20): 8180 - 8185. [Abstract] [Full Text] [PDF]

				T. Toyooka, T. Awai, T. Kanai, T. Imanaka, and H. Hori Stabilization of tRNA (m1G37) methyltransferase [TrmD] from Aquifex aeolicus by an intersubunit disulfide bond formation Genes Cells, August 1, 2008; 13(8): 807 - 816. [Abstract] [Full Text] [PDF]

				H. Takeda, T. Toyooka, Y. Ikeuchi, S.-i. Yokobori, K. Okadome, F. Takano, T. Oshima, T. Suzuki, Y. Endo, and H. Hori The substrate specificity of tRNA (m1G37) methyltransferase (TrmD) from Aquifex aeolicus Genes Cells, December 1, 2006; 11(12): 1353 - 1365. [Abstract] [Full Text] [PDF]

				K. Watanabe, O. Nureki, S. Fukai, Y. Endo, and H. Hori Functional Categorization of the Conserved Basic Amino Acid Residues in TrmH (tRNA (Gm18) Methyltansferase) Enzymes J. Biol. Chem., November 10, 2006; 281(45): 34630 - 34639. [Abstract] [Full Text] [PDF]

				A. ALEXANDROV, E. J. GRAYHACK, and E. M. PHIZICKY tRNA m7G methyltransferase Trm8p/Trm82p: Evidence linking activity to a growth phenotype and implicating Trm82p in maintaining levels of active Trm8p RNA, May 1, 2005; 11(5): 821 - 830. [Abstract] [Full Text] [PDF]