title: Molecular determinants of dihydrouridine synthase activity.
abstract: Dihydrouridine is one of the most abundant modified bases in tRNA. However, little is known concerning the biochemistry of dihydrouridine synthase (DUS) enzymes. To identify molecular determinants that are necessary for DUS activity, we have developed a DUS-complementation assay in Escherichia coli. Using this assay, we have identified amino-acid residues that are critical for the activity of YjbN, an E. coli DUS. We also show that the aq1598 gene product, a putative DUS from Aquifex aeolicus, catalyzes dihydrouridine formation, providing the first biochemical demonstration that A. aeolicus encodes an active DUS.
authors.affiliation: Department of Chemistry, Amherst College, MA 01002, USA.
authors.forename: Dan F
authors.initials: DF
authors.lastname: Savage
authors.forename: Valérie
authors.initials: V
authors.lastname: de Crécy-Lagard
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Bishop
mesh_terms: D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005816:Genetic Complementation Test; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000096:biosynthesis / Q000235:genetics*; D017434:Protein Structure, Tertiary; D014529:Uridine / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000235:genetics
chemical_list: D029968:Escherichia coli Proteins; C010922:5,6-dihydrouridine; D010088:Oxidoreductases; C462500:tRNA-dihydrouridine synthase; D014529:Uridine