Temperature sensitivity of protein synthesis initiation in the reticulocyte lysate system. Reduced formation of the 40 S ribosomal subunit - Met-tRNAf complex at an elevated temperature.
Analysis of protein synthesis in the rabbit reticulocyte lysate system revealed the existence of a temperature-sensitive step in chain initiation which became irreversibly inactivated in the incubation at 42 degrees C. This inactivation of initiation was accompanied by a marked reduction in formation of the 40 S ribosomal subunit - Met-tRNAf complex. Decreased protein synthesis and a decrease in formation of the 40 S complex were also evident in unfortified lysates which had been prewarmed at 42 degrees C prior to protein synthesis. Hemin did not protect such lysates. The addition of supernatant fraction of a fresh lysate did not promote recovery of the reduced protein synthesis by such prewarmed lysates. Moreover, the addition of supernatant fraction prewarmed at 42 degrees C in the presence of added hemin caused little inhibition of protein synthesis by fresh lysate. The results indicate that the supernatant fraction is not involved in the inactivation.
D000818:Animals; D001665:Binding Sites; D007700:Kinetics; D008715:Methionine; D010441:Peptide Chain Elongation, Translational; D010442:Peptide Chain Initiation, Translational; D012343:RNA, Transfer / Q000097:blood*; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D013696:Temperature
D012343:RNA, Transfer; D008715:Methionine