Domains of phenylalanyl‐tRNA synthetase from Thermus thermophilus required for aminoacylation

The contribution of entire domains or particular amino acid residues of the phenylalanyl-tRNA synthetase (FRS) from Thermus thermophilus to the interaction with tRNA(Phe) was studied. Removal of domain 8 of the beta subunit resulted in drastic reduction of the dissociation constant of the FRS x tRNA(Phe) complex. Neither the removal of arginine 2 of the beta subunit, which makes the only major contact between domains beta1-5 and the tRNA, nor the replacement of the conserved proline 473 by glycine had an influence on the aminoacylation activity of the FRS. Thus, the body comprising domains 1-5 of the beta subunit may not be essential for efficient aminoacylation of tRNA(Phe) by the FRS and rather be involved in other functions.