[Alkylation of tRNA-Phe free and bound to phenylalanyl-tRNA synthetase with 4-(N-2-chloroethyl-N-methylamino)benzylamine].

: Reactivities toward the alkylating reagent 4-(N-2-chloroethyl-N-methylamino)benzylamine of guanosine residues in the tRNAPhe free and bound to the phenylalanyl-tRNA synthetase were determined. This highly efficient reagent modifies mainly guanosine in single-stranded as well as in helical regions of tRNAs. The reaction is sensitive to the elements of the macrostructure of tRNAs. It is found the phenylalanyl-tRNA synthetase protects the D-stem of the tRNAPhe (guanosines G10, G22, G24) from alkylation.