title: An extended dsRBD is required for post-transcriptional modification in human tRNAs.
abstract: In tRNA, dihydrouridine is a conserved modified base generated by the post-transcriptional reduction of uridine. Formation of dihydrouridine 20, located in the D-loop, is catalyzed by dihydrouridine synthase 2 (Dus2). Human Dus2 (HsDus2) expression is upregulated in lung cancers, offering a growth advantage throughout its ability to interact with components of the translation apparatus and inhibit apoptosis. Here, we report the crystal structure of the individual domains of HsDus2 and their functional characterization. HsDus2 is organized into three major modules. The N-terminal catalytic domain contains the flavin cofactor involved in the reduction of uridine. The second module is the conserved α-helical domain known as the tRNA binding domain in HsDus2 homologues. It is connected via a flexible linker to an unusual extended version of a dsRNA binding domain (dsRBD). Enzymatic assays and yeast complementation showed that the catalytic domain binds selectively NADPH but cannot reduce uridine in the absence of the dsRBD. While in Dus enzymes from bacteria, plants and fungi, tRNA binding is essentially achieved by the α-helical domain, we showed that in HsDus2 this function is carried out by the dsRBD. This is the first reported case of a tRNA-modifying enzyme carrying a dsRBD used to bind tRNAs.
authors.affiliation: Laboratoire de Chimie des Processus Biologiques, CNRS-UMR 8229, Collège De France, France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Bou-Nader
authors.affiliation: Laboratoire de Chimie des Processus Biologiques, CNRS-UMR 8229, Collège De France, France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Pecqueur
authors.affiliation: Sorbonne Universités, UPMC Univ. Paris 06, IBPS, UMR8256, Biology of Aging and Adaptation, F-75005 Paris, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Bregeon
authors.affiliation: Université de Lille-Nord de France, CNRS UMR 8576, Institut Fédératif de Recherches 147, Villeneuve d'Ascq, France.
authors.forename: Amina
authors.initials: A
authors.lastname: Kamah
authors.affiliation: Institut de Chimie des Substances Naturelles, Centre de Recherche de Gif, CNRS, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Guérineau
authors.affiliation: Laboratoire de Chimie des Processus Biologiques, CNRS-UMR 8229, Collège De France, France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Golinelli-Pimpaneau
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91190 Gif-sur-Yvette, France.
authors.forename: Beatriz G
authors.initials: BG
authors.lastname: Guimarães
authors.affiliation: Laboratoire de Chimie des Processus Biologiques, CNRS-UMR 8229, Collège De France, France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Fontecave
authors.affiliation: Laboratoire de Chimie des Processus Biologiques, CNRS-UMR 8229, Collège De France, France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France djemel.hamdane@college-de-france.fr.
authors.forename: Djemel
authors.initials: D
authors.lastname: Hamdane
mesh_terms: D001665:Binding Sites; D020134:Catalytic Domain; D005486:Flavin Mononucleotide / Q000737:chemistry; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012323:RNA Processing, Post-Transcriptional; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D005486:Flavin Mononucleotide; D012343:RNA, Transfer; D010088:Oxidoreductases; C107530:SMM1 protein, S cerevisiae; C526987:tRNA dihydrouridine synthase-2, human