Effect of X-radiation on Transfer Ribonucleic Acid

Summary When aqueous solutions of uncharged transfer ribonucleic acids of liver, yeast and E. coli origin were irradiated, their acceptor activities for leucine, phenylalanine and lysine were inhibited by different amounts. Both rate and final extent of acceptance were reduced. The degree of inhibition is a function of dose and is less for irradiation in nitrogen then in air. Lysine acceptor activity showed the greatest sensitivity in t-RNA from all three sources. Exposure of uncharged liver t-RNA to 50 krads x-radiation resulted in about 50 per cent inhibition of its ability to transfer 14C-L-lysine to polylysine in the presence of poly A and a liver ribosomal system. Results indicated radiation damage to the regions associated with transfer function as well as to acceptor sites. By irradiation of 14C-lysine-charged t-RNA it was possible to show that both the ribosomal binding site and the anticodon region were sensitive to ionizing radiation.