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Biomolecules 2017, 7(1), 23;

Transfer RNA methyltransferases with a SpoU‐TrmD  (SPOUT) fold and their modified nucleosides in  tRNA

Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo‐cho, Matsuyama, Ehime 790‐8577, Japan
Academic Editor: Valérie de Crécy‐Lagard
Received: 7 January 2017 / Accepted: 23 February 2017 / Published: 28 February 2017
(This article belongs to the Collection RNA Modifications)
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The existence of SpoU‐TrmD (SPOUT) RNA methyltransferase superfamily was first predicted by bioinformatics. SpoU is the previous name of TrmH, which catalyzes the 2’‐Omethylation of ribose of G18 in tRNA; TrmD catalyzes the formation of N1‐methylguanosine at position 37 in tRNA. Although SpoU (TrmH) and TrmD were originally considered to be unrelated, the bioinformatics study suggested that they might share a common evolution origin and form a single superfamily. The common feature of SPOUT RNA methyltransferases is the formation of a deep trefoil knot in the catalytic domain. In the past decade, the SPOUT RNA methyltransferase superfamily has grown; furthermore, knowledge concerning the functions of their modified nucleosides in tRNA has also increased. Some enzymes are potential targets in the design of antibacterial drugs. In humans, defects in some genes may be related to carcinogenesis. In this review, recent findings on the tRNA methyltransferases with a SPOUT fold and their methylated nucleosides in tRNA, including classification of tRNA methyltransferases with a SPOUT fold; knot structures, domain arrangements, subunit structures and reaction mechanisms; tRNA recognition mechanisms, and functions of modified nucleosides synthesized by this superfamily, are summarized. Lastly, the future perspective for studies on tRNA modification enzymes are considered. View Full-Text
Keywords: knot; methyltransferase; SpoU‐TrmD; RNA modification; tRNA knot; methyltransferase; SpoU‐TrmD; RNA modification; tRNA

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Hori, H. Transfer RNA methyltransferases with a SpoU‐TrmD  (SPOUT) fold and their modified nucleosides in  tRNA. Biomolecules 2017, 7, 23.

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