title: A [3Fe-4S] cluster is required for tRNA thiolation in archaea and eukaryotes.
abstract: The sulfur-containing nucleosides in transfer RNA (tRNAs) are present in all three domains of life; they have critical functions for accurate and efficient translation, such as tRNA structure stabilization and proper codon recognition. The tRNA modification enzymes ThiI (in bacteria and archaea) and Ncs6 (in archaea and eukaryotic cytosols) catalyze the formation of 4-thiouridine (s4U) and 2-thiouridine (s2U), respectively. The ThiI homologs were proposed to transfer sulfur via cysteine persulfide enzyme adducts, whereas the reaction mechanism of Ncs6 remains unknown. Here we show that ThiI from the archaeonMethanococcus maripaludiscontains a [3Fe-4S] cluster that is essential for its tRNA thiolation activity. Furthermore, the archaeal and eukaryotic Ncs6 homologs as well as phosphoseryl-tRNA (Sep-tRNA):Cys-tRNA synthase (SepCysS), which catalyzes the Sep-tRNA to Cys-tRNA conversion in methanogens, also possess a [3Fe-4S] cluster similar to the methanogenic archaeal ThiI. These results suggest that the diverse tRNA thiolation processes in archaea and eukaryotic cytosols share a common mechanism dependent on a [3Fe-4S] cluster for sulfur transfer.
authors: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803; yuchenliu@lsu.edu dieter.soll@yale.edu.
authors: Yuchen
authors: Y
authors: Liu
authors: Department of Chemistry, Yale University, New Haven, CT 06520.
authors: David J
authors: DJ
authors: Vinyard
authors: Department of Chemistry, Yale University, New Haven, CT 06520.
authors: Megan E
authors: ME
authors: Reesbeck
authors: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520.
authors: Tateki
authors: T
authors: Suzuki
authors: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520.
authors: Kasidet
authors: K
authors: Manakongtreecheep
authors: Department of Chemistry, Yale University, New Haven, CT 06520.
authors: Patrick L
authors: PL
authors: Holland
authors: Department of Chemistry, Yale University, New Haven, CT 06520.|Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520.
authors: Gary W
authors: GW
authors: Brudvig
authors: Department of Chemistry, Yale University, New Haven, CT 06520; yuchenliu@lsu.edu dieter.soll@yale.edu.|Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520.
authors: Dieter
authors: D
authors: Söll
keywords: CTU1; iron-sulfur cluster; tRNA modification; thionucleosides