Aminoacyl-tRNA synthetase-induced cleavage of tRNA

Aminoacyl-tRNA synthetases interact with their cognate tRNAs in a highly specific fashion. We have examined the phenomenon that upon complex formation E. coli glutamlnyl-tRNA synthetase destabilizes tRNAG in causing chain scissions in the presence of Mg2+ ions. The phosphodiester bond cleavage produces 3'-phosphate and 5'-hydroxyl ends. This kind of experiment is useful for detecting conformational changes in tRNA. Our results show that the cleavage is synthetase-specific, that mutant and wild-type tRNAGln species can assume a different conformation, and that modified nucleosides in tRNA enhance the structural stability of the molecule.