Shiga toxin from Shigella dysenteriae 1 inhibits protein synthesis in reticulocyte lysates by inactivation of aminoacyl-tRNA binding.
Inhibition of the peptide elongation cycle of eukaryotic protein synthesis by Shiga toxin from Shigella dysenteriae 1 was examined in toxin-treated reticulocyte lysate mixtures. Peptidyl transferase activity of toxin-treated ribosomes was measured by following the decrease in peptidyl-tRNA concentrations when puromycin was added after incubation with toxin. Concentrations of [3H]leucine-labeled peptidyl-tRNA were measured by extraction with cetyltrimethylammonium bromide. The data suggest that Shiga toxin inhibited aminoacyl-tRNA binding. Toxin-treated ribosomes retained peptidyl transferase activity, and toxin did not block translocation. Furthermore, no inhibition of initiation of protein synthesis could be observed. Finally, Shiga toxin had no detectable nucleolytic effect on polysomal 28S rRNA, nor was hydrolysis of 5.8S or 5S rRNA observed.
Brown
J E
JE
Department of Biological Chemistry, Walter Reed Army Institute of Research, Washington DC 20307-5100.
Obrig
T G
TG
Ussery
M A
MA
Moran
T P
TP
D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D066298:In Vitro Techniques; D011500:Protein Synthesis Inhibitors; D012335:RNA, Ribosomal / Q000187:drug effects; D012346:RNA, Transfer, Amino Acyl / Q000097:blood; D011817:Rabbits; D012156:Reticulocytes / Q000187:drug effects / Q000378:metabolism; D022603:Shiga Toxins; D012762:Shigella dysenteriae
D001427:Bacterial Toxins; D011500:Protein Synthesis Inhibitors; D012335:RNA, Ribosomal; D012346:RNA, Transfer, Amino Acyl; D022603:Shiga Toxins