Presence and location of modified nucleotides in Escherichia coli tmRNA: structural mimicry with tRNA acceptor branches.

Abstract : Escherichia coli tmRNA functions uniquely as both tRNA and mRNA and possesses structural elements similar to canonical tRNAs. To test whether this mimicry extends to post-transcriptional modification, the technique of combined liquid chromatography/ electrospray ionization mass spectrometry (LC/ESIMS) and sequence data were used to determine the molecular masses of all oligonucleotides produced by RNase T1 hydrolysis with a mean error of 0.1 Da. Thus, this allowed for the detection, chemical characterization and sequence placement of modified nucleotides which produced a change in mass. Also, chemical modifications were used to locate mass-silent modifications. The native E.coli tmRNA contains two modified nucleosides, 5-methyluridine and pseudouridine. Both modifications are located within the proposed tRNA-like domain, in a seven-nucleotide loop mimicking the conserved sequence of T loops in canonical tRNAs. Although tmRNA acceptor branches (acceptor stem and T stem-loop) utilize different architectural rules than those of canonical tRNAs, their conformations in solution may be very similar. A comparative structural and functional analysis of unmodified tmRNA made by in vitro transcription and native E.coli tmRNA suggests that one or both of these post-transcriptional modifications may be required for optimal stability of the acceptor branch which is needed for efficient aminoacylation.
Type de document :
Article dans une revue
EMBO J, 1998, 17 (11), pp.3188-96. 〈10.1093/emboj/17.11.3188〉
Liste complète des métadonnées

Littérature citée [38 références]  Voir  Masquer  Télécharger
Contributeur : Annick Lefevre <>
Soumis le : vendredi 20 juillet 2012 - 12:31:41
Dernière modification le : vendredi 23 mars 2018 - 13:56:12
Document(s) archivé(s) le : vendredi 16 décembre 2016 - 01:30:16


 Accès restreint
Fichier visible le : jamais

Connectez-vous pour demander l'accès au fichier




Brice Felden, Kyoko Hanawa, John Atkins, Hyouta Himeno, Akira Muto, et al.. Presence and location of modified nucleotides in Escherichia coli tmRNA: structural mimicry with tRNA acceptor branches.. EMBO J, 1998, 17 (11), pp.3188-96. 〈10.1093/emboj/17.11.3188〉. 〈inserm-00719626〉



Consultations de la notice