title: Effects of polyamines from Thermus thermophilus, an extreme-thermophilic eubacterium, on tRNA methylation by tRNA (Gm18) methyltransferase (TrmH).
abstract: Thermus thermophilus is an extreme-thermophilic eubacterium, which grows at a wide range of temperatures (50-83°C). This thermophile produces various polyamines including long and branched polyamines. In tRNAs from T. thermophilus, three distinct modifications, 2'-O-methylguanosine at position 18 (Gm18), 5-methyl-2-thiouridine at position 54 and N(1)-methyladenosine at position 58, are assembled at the elbow region to stabilize the L-shaped tRNA structure. However, the structures of unmodified tRNA precursors are disrupted at high temperatures. We hypothesize that polyamine(s) might have a positive effect on the modification process of unmodified tRNA transcript. We investigated the effects of eight polyamines on Gm18 formation in the yeast tRNA(Phe) transcript by tRNA (Gm18) methyltransferase (TrmH). Higher concentrations of linear polyamines inhibited TrmH activity at 55°C, while optimum concentration increased TrmH activity at 45-75°C. Exceptionally, caldohexamine, a long polyamine, did not show any positive effect on the TrmH activity at 55°C. However, temperature-dependent experiments revealed that 1 mM caldohexamine increased TrmH activity at 60-80°C. Furthermore, 0.25 mM tetrakis(3-aminopropy)ammonium, a branched polyamine, increased TrmH activity at a broad range of temperatures (40-85°C). Thus, caldohexamine and tetrakis(3-aminopropy)ammonium were found to enhance the TrmH activity at high temperatures.
authors.affiliation: Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577; hori@eng.ehime-u.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hori
authors.affiliation: Faculty of Pharmacy, Chiba Institute of Science, 15-8 Shiomi-cho, Choshi, Chiba; and.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Terui
authors.affiliation: Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577;
authors.forename: Chisato
authors.initials: C
authors.lastname: Nakamoto
authors.affiliation: Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577;
authors.forename: Chikako
authors.initials: C
authors.lastname: Iwashita
authors.affiliation: Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577;
authors.forename: Anna
authors.initials: A
authors.lastname: Ochi
authors.affiliation: Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577;
authors.forename: Kazunori
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Institute of Environmental Microbiology, Kyowa Kako Co. Ltd., Tadao 2-15-5, Machida 194-0035, Japan tairo.oshima@kyowa-kako.co.jp.
authors.forename: Tairo
authors.initials: T
authors.lastname: Oshima
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D015317:Biogenic Polyamines / Q000737:chemistry* / Q000378:metabolism; D006358:Hot Temperature; D008745:Methylation; D012323:RNA Processing, Post-Transcriptional; D012329:RNA, Bacterial / Q000737:chemistry* / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry* / Q000378:metabolism; D016963:Thermus thermophilus / Q000737:chemistry* / Q000378:metabolism; D012359:tRNA Methyltransferases / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D015317:Biogenic Polyamines; D012329:RNA, Bacterial; D012343:RNA, Transfer; D012359:tRNA Methyltransferases
keywords: RNA modification; methyltransferase; polyamine; tRNA; thermophile