1. The relation between catalytic activity and gene regulation in the case of E coli threonyl-tRNA synthetase
- Author
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J. Dondon, Chantal Ehresmann, Hervé Moine, Pascale Romby, Marianne Grunberg-Manago, Jean-Pierre Ebel, Mathias Springer, Pascale Lesage, Bernard Ehresmann, and M. Graffe
- Subjects
Binding Sites ,Base Sequence ,Molecular Sequence Data ,RNA ,Aminoacylation ,Translation (biology) ,General Medicine ,Gene Expression Regulation, Bacterial ,Biology ,Biochemistry ,Ribosome ,Ribosomal binding site ,RNA, Bacterial ,Protein Biosynthesis ,Transfer RNA ,Translational regulation ,Mutation ,Escherichia coli ,Threonine-tRNA Ligase ,Nucleic Acid Conformation ,RNA, Messenger ,Binding site - Abstract
The expression of the gene for threonyl-tRNA synthetase ( thrS ) has previously been shown as being negatively autoregulated at the translational level. The region of the thrS leader mRNA responsible for that control is located immediately upstream of the ribosomal binding site, and was proposed to fold in a tRNA Thr anticodon arm-like structure. The present paper reviews experiments using enzymatic and chemical probes that prove the existence of a tRNA Thr anticodon-like structure in the thrS mRNA. These structural studies have also shown the presence of another arm upstream in the leader mRNA that has striking similarities with the acceptor arm of the tRNA Thr isoacceptors. This second arm was shown, by mutational analysis, to also be involved in thrS regulation. Footprinting experiments have shown that both the anticodon-like and the acceptor-like arms interact with the synthetase. Finally, the similarity of the interaction of the synthetase with its 2 RNA ligands (mRNA and tRNA) has been investigated by selecting and studying mutants of the synthetase itself. The observed correlation between regulatory and aminoacylation defects in these mutants strongly suggests that the synthetase recognizes similar regions of its 2 RNA ligands in an analogous manner.
- Published
- 1990