Species-specific identity elements of tRNA(Trp)

Through the comparisons among 91 tRNA(Trp) sequences from prokaryotes, arch ea and eukaryotes, the potential species-specific identity elements of tRNA (Trp) are found to be located within acceptor stem, dihydrouridine (D) stem , anticodon(AC) stem and discriminator base. Mutagenesis of B. subtilis tRN A(Trp) to the eukaryotic consensus sequence, in vitro transcription and enz ymatic assay of tRNA(Trp) toward different tryptophanyl-tRNA synthetases (T rpRS) were employed to shed light on these species-specific identity elemen ts and demonstrate the accurate recognition and the coevolution between tRN A and TrpRS. B. subtilis tRNA(Trp) with its acceptor stem and discriminator base transplanted by eukaryotic counterparts exhibited diminished reactivi ty toward B. subtilis enzyme but could be efficiently aminoacylated by rat liver crude enzyme. In contrast, B. subtilis tRNA(Trp) analog with the euka ryotic anticodon stem and D stem retains its recognition by B. subtilis enz yme. The results provide a strong evidence that the species-specific identi ty elements of tRNA(Trp) are orientated within the acceptor stem and discri minator base of tRNA(Trp), and the anticodon stem and D stem are of little importance to the interaction between tRNA(Trp) and its cognate synthetase (TrpRS).