title: An aminoacyl-tRNA synthetase-like protein encoded by the Escherichia coli yadB gene glutamylates specifically tRNAAsp.
abstract: The product of the Escherichia coli yadB gene is homologous to the N-terminal part of bacterial glutamyl-tRNA synthetases (GluRSs), including the Rossmann fold with the acceptor-binding domain and the stem-contact fold. This GluRS-like protein, which lacks the anticodon-binding domain, does not use tRNA(Glu) as substrate in vitro nor in vivo, but aminoacylates tRNA(Asp) with glutamate. The yadB gene is expressed in wild-type E. coli as an operon with the dksA gene, which encodes a protein involved in the general stress response by means of its action at the translational level. The fate of the glutamylated tRNA(Asp) is not known, but its incapacity to bind elongation factor Tu suggests that it is not involved in ribosomal protein synthesis. Genes homologous to yadB are present only in bacteria, mostly in Proteobacteria. Sequence alignments and phylogenetic analyses show that the YadB proteins form a distinct monophyletic group related to the bacterial and organellar GluRSs (alpha-type GlxRSs superfamily) with ubiquitous function as suggested by the similar functional properties of the YadB homologue from Neisseria meningitidis.
authors.affiliation: Département de Biochimie et Microbiologie, Faculté de Sciences et de Génie, Centre de Recherche sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Quebec, QC, Canada G1K 7P4.
authors.forename: Daniel Y
authors.initials: DY
authors.lastname: Dubois
authors.forename: Mickaël
authors.initials: M
authors.lastname: Blaise
authors.forename: Hubert D
authors.initials: HD
authors.lastname: Becker
authors.forename: Valérie
authors.initials: V
authors.lastname: Campanacci
authors.forename: Gérard
authors.initials: G
authors.lastname: Keith
authors.forename: Richard
authors.initials: R
authors.lastname: Giegé
authors.forename: Christian
authors.initials: C
authors.lastname: Cambillau
authors.forename: Jacques
authors.initials: J
authors.lastname: Lapointe
authors.forename: Daniel
authors.initials: D
authors.lastname: Kern
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D020652:Peptide Elongation Factor 2 / Q000378:metabolism; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D012349:RNA, Transfer, Asp / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D020652:Peptide Elongation Factor 2; D012333:RNA, Messenger; D012349:RNA, Transfer, Asp; D018698:Glutamic Acid; C487511:YadB protein, E coli; D000604:Amino Acyl-tRNA Synthetases