Nucleic Acids Research Advance Access published June 4, 2010
Nucleic Acids Research, 2010, 1–11 doi:10.1093/nar/gkq451

New archaeal methyltransferases forming 1-methyladenosine or 1-methyladenosine and 1-methylguanosine at position 9 of tRNA
Morgane Kempenaers1, Martine Roovers2, Yamina Oudjama2, Karolina L. Tkaczuk3,4, Janusz M. Bujnicki3,5 and Louis Droogmans1,*
´ Laboratoire de Microbiologie, Universite Libre de Bruxelles (ULB), 2Institut de Recherches Microbiologiques Jean-Marie Wiame, Avenue E. Gryson 1, B-1070 Bruxelles, Belgium, 3International Institute of Molecular and Cell Biology in Warsaw, Trojdena 4 St., PL-02-109 Warsaw, 4Institute of Technical Biochemistry, Technical University of Lodz, B. Stefanowskiego 4/10, PL-90-924 Lodz and 5Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, PL-61-614 Poznan, Poland
Received February 22, 2010; Revised May 9, 2010; Accepted May 10, 2010
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ABSTRACT Two archaeal tRNA methyltransferases belonging to the SPOUT superfamily and displaying unexpected activities are identified. These enzymes are orthologous to the yeast Trm10p methyltransferase, which catalyses the formation of 1-methylguanosine at position 9 of tRNA. In contrast, the Trm10p orthologue from the crenarchaeon Sulfolobus acidocaldarius forms 1-methyladenosine at the same position. Even more surprisingly, the Trm10p orthologue from the euryarchaeon Thermococcus kodakaraensis methylates the N1-atom of either adenosine or guanosine at position 9 in different tRNAs. This is to our knowledge the first example of a tRNA methyltransferase with a broadened nucleoside recognition capability. The evolution of tRNA methyltransferases methylating the N1 atom of a purine residue is discussed. INTRODUCTION Cellular RNAs possess numerous chemically modified nucleosides, but the largest number and