title: Biosynthesis of wybutosine, a hyper-modified nucleoside in eukaryotic phenylalanine tRNA.
abstract: Wybutosine (yW) is a tricyclic nucleoside with a large side chain found at the 3'-position adjacent to the anticodon of eukaryotic phenylalanine tRNA. yW supports codon recognition by stabilizing codon-anticodon interactions during decoding on the ribosome. To identify genes responsible for yW synthesis from uncharacterized genes of Saccharomyces cerevisiae, we employed a systematic reverse genetic approach combined with mass spectrometry ('ribonucleome analysis'). Four genes YPL207w, YML005w, YGL050w and YOL141w (named TYW1, TYW2, TYW3 and TYW4, respectively) were essential for yW synthesis. Mass spectrometric analysis of each modification intermediate of yW revealed its sequential biosynthetic pathway. TYW1 is an iron-sulfur (Fe-S) cluster protein responsible for the tricyclic formation. Multistep enzymatic formation of yW from yW-187 could be reconstituted in vitro using recombinant TYW2, TYW3 and TYW4 with S-adenosylmethionine, suggesting that yW synthesis might proceed through sequential reactions in a complex formed by multiple components assembled with the precursor tRNA. This hypothesis is also supported by the fact that plant ortholog is a large fusion protein consisting of TYW2 and TYW3 with the C-terminal domain of TYW4.
authors.affiliation: Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Noma
authors.forename: Yohei
authors.initials: Y
authors.lastname: Kirino
authors.forename: Yoshiho
authors.initials: Y
authors.lastname: Ikeuchi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009705:Nucleosides / Q000096:biosynthesis* / Q000737:chemistry; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012360:RNA, Transfer, Phe / Q000737:chemistry* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D009705:Nucleosides; D010940:Plant Proteins; D012360:RNA, Transfer, Phe; D011994:Recombinant Proteins; C467591:wybutosine