A minimalist glutamyl-tRNA synthetase dedicated to aminoacylation of the tRNAAsp QUC anticodon.
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.
Blaise
Mickaël
M
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.
Becker
Hubert Dominique
HD
Keith
Gérard
G
Cambillau
Christian
C
Lapointe
Jacques
J
Giegé
Richard
R
Kern
Daniel
D
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
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