title: Selenomodification of tRNA in archaea requires a bipartite rhodanese enzyme.
abstract: 5-Methylaminomethyl-2-selenouridine (mnm(5)Se(2)U) is found in the first position of the anticodon in certain tRNAs from bacteria, archaea and eukaryotes. This selenonucleoside is formed in Escherichia coli from the corresponding thionucleoside mnm(5)S(2)U by the monomeric enzyme YbbB. This nucleoside is present in the tRNA of Methanococcales, yet the corresponding 2-selenouridine synthase is unknown in archaea and eukaryotes. Here we report that a bipartite ybbB ortholog is present in all members of the Methanococcales. Gene deletions in Methanococcus maripaludis and in vitro activity assays confirm that the two proteins act in trans to form in tRNA a selenonucleoside, presumably mnm(5)Se(2)U. Phylogenetic data suggest a primal origin of seleno-modified tRNAs.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA.
authors.forename: Dan
authors.initials: D
authors.lastname: Su
authors.forename: Temitope T
authors.initials: TT
authors.lastname: Ojo
authors.forename: Dieter
authors.initials: D
authors.lastname: Söll
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hohn
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019843:Archaeal Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D008025:Ligases / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism; D017017:Methanococcus / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016566:Organoselenium Compounds / Q000737:chemistry / Q000378:metabolism*; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012343:RNA, Transfer / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D012643:Selenium / Q000378:metabolism*; D016415:Sequence Alignment; D013884:Thiosulfate Sulfurtransferase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014529:Uridine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D016566:Organoselenium Compounds; C043608:5-((methylamino)methyl)-2-selenouridine; D012343:RNA, Transfer; D013884:Thiosulfate Sulfurtransferase; D008025:Ligases; D012643:Selenium; D014529:Uridine