Direct evaluation of tRNA aminoacylation status by the T-box riboswitch using tRNA-mRNA stacking and steric readout.
Mol Cell
; 55(1): 148-55, 2014 Jul 03.
Article
em En
| MEDLINE
| ID: mdl-24954903
ABSTRACT
T-boxes are gene-regulatory mRNA elements with which Gram-positive bacteria sense amino acid availability. T-boxes have two functional domains. Stem I recognizes the overall shape and anticodon of tRNA, while a 3' domain evaluates its aminoacylation status, overcoming an otherwise stable transcriptional terminator if the bound tRNA is uncharged. Although T-boxes are believed to evaluate tRNA charge status without using any proteins, this has not been demonstrated experimentally because of the instability of aminoacyl-tRNA. Using a simple method to prepare homogeneous aminoacyl-tRNA, we show that the Bacillus subtilis glyQS T-box functions independently of any tRNA-binding protein. Comparison of aminoacyl-tRNA analogs demonstrates that the T-box detects the molecular volume of tRNA 3'-substituents. Calorimetry and fluorescence lifetime analysis of labeled RNAs shows that the tRNA acceptor end coaxially stacks on a helix in the T-box 3' domain. This intimate intermolecular association, selective for uncharged tRNA, stabilizes the antiterminator conformation of the T-box.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Bacillus subtilis
/
RNA de Transferência
/
Riboswitch
Idioma:
En
Revista:
Mol Cell
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Estados Unidos