Phenylalanyl-tRNA synthetase from E. coli MRE-600: localization of the phenylalanine binding sites on the subunits by affinity reagents.

The phenylalanine and the phenylalanyl-tRNAPhe binding sites on the subunits of phenylalanyl-tRNA synthetase from E. coli MRE-600 were localized using p-azidoanilidate of [14C]phenylalanine and N-bromoacetyl-[14C]phenylalanyl-tRNAPhe. The phenylalanine recognizing site was shown to be situated on the alpha subunit of the enzyme in close proximity to the contact region of the alpha and beta subunits and the phenylalanyl-tRNAPhe recognizing site on the beta subunit. Transfer of the aminoacyl moiety from the alpha subunit to the beta subunit of the enzyme was assumed to take place in the process of catalysis of the aminoacylation reaction.