Effect of γ-radiation on the Structure and Function of Isolated Rat-liver Transfer Ribonucleic Acid

Summary

In rat-liver t-RNA γ-irradiated in dilute aqueous solution, structural changes are revealed by polyacrylamide gel electrophoresis. A new, fast-moving and non-dialysable component appears, the relative amount of which is a function of both the radiation dose and t-RNA concentration during irradiation. Part of the structural damage remains masked but can be demonstrated by heat treatment. The t-RNA amino-acid acceptor activity shows different degrees of radiosensitivity, depending on whether irradiation takes place in air, nitrogen or nitrous oxide. This suggests that the acceptor function is in the first place damaged by e_aq⁻. The lysyl-t-RNA bond was also studied under similar experimental conditions. Irradiation produced both dissociation of the bond and a change in the binding force in the remaining, non-dissociating fraction.