Effects of a conformational change in tRNA on its aminoacylation capacity: a study using enzymatically reconstructed variants of T. utilis tRNATyr.

Variants of T. utilis tRNATyr containing deletion or substitution of the "conserved" sequence Gm18-G19 in the D-loop have been enzymatically reconstructed in vitro. Conformational analyses of these variants by measuring melting profiles, electrophoretic mobility in "native" polyacrylamide gels, and by the analysis of RNase T1 digestion patterns on sequencing gels laid a stress on the significance of the Gm18-G19 sequence for the maintenance of L-shaped tertiary structure of tRNATyr. Aminoacylation assays with the variant tRNAs at various temperatures revealed that the highly ordered tertiary structure is needed for full aminoacylation capacity.