title: A minimalist glutamyl-tRNA synthetase dedicated to aminoacylation of the tRNAAsp QUC anticodon.
abstract: Escherichia coli encodes YadB, a protein displaying 34% identity with the catalytic core of glutamyl-tRNA synthetase but lacking the anticodon-binding domain. We show that YadB is a tRNA modifying enzyme that evidently glutamylates the queuosine residue, a modified nucleoside at the wobble position of the tRNA(Asp) QUC anticodon. This conclusion is supported by a variety of biochemical data and by the inability of the enzyme to glutamylate tRNA(Asp) isolated from an E.coli tRNA-guanosine transglycosylase minus strain deprived of the capacity to exchange guanosine 34 with queuosine. Structural mimicry between the tRNA(Asp) anticodon stem and the tRNA(Glu) amino acid acceptor stem in prokaryotes encoding YadB proteins indicates that the function of these tRNA modifying enzymes, which we rename glutamyl-Q tRNA(Asp) synthetases, is conserved among prokaryotes.
authors.affiliation: Département Mécanismes et Macromolécules de la Synthèse Protéique et Cristallogenèse, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 15 Rue René Descartes, F-67084 Strasbourg Cedex, France.
authors.forename: Mickaël
authors.initials: M
authors.lastname: Blaise
authors.forename: Hubert Dominique
authors.initials: HD
authors.lastname: Becker
authors.forename: Gérard
authors.initials: G
authors.lastname: Keith
authors.forename: Christian
authors.initials: C
authors.lastname: Cambillau
authors.forename: Jacques
authors.initials: J
authors.lastname: Lapointe
authors.forename: Richard
authors.initials: R
authors.lastname: Giegé
authors.forename: Daniel
authors.initials: D
authors.lastname: Kern
mesh_terms: D000215:Acylation; D000926:Anticodon / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D005075:Biological Evolution; D017124:Conserved Sequence; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics*; D005975:Glutamate-tRNA Ligase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018716:Molecular Mimicry; D009704:Nucleoside Q / Q000235:genetics / Q000378:metabolism*; D010504:Periodic Acid / Q000494:pharmacology; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012349:RNA, Transfer, Asp / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012352:RNA, Transfer, Glu / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D000926:Anticodon; D012329:RNA, Bacterial; D012349:RNA, Transfer, Asp; D012352:RNA, Transfer, Glu; D010504:Periodic Acid; D009704:Nucleoside Q; C009288:metaperiodate; D005975:Glutamate-tRNA Ligase