Inhibition of Protein Synthesis by a Vero Toxin (VT2 or Shiga-like Toxin II) Produced by Escherichia Coli O157:H7 at the Level of Elongation Factor 1-dependent Aminoacyl-tRNA Binding to Ribosomes

A Vero toxin (VT2 or Shiga-like toxin II) from Escherichia coli O157:H7 was shown to inhibit protein synthesis in a rabbit reticulocyte lysate, but not in wheat germ or Ercherichia coli lysates. The toxin, VT2, inactivated 60S ribosomal subunits of rabbit reticulocytes. The site of inhibition of protein synthesis by VT2 was shown to be elongation factor 1-dependent aminoacyl-tRNA binding to ribosomes. VT2 did not affect Met-tRNAf binding to ribosomes, non-enzymatic binding of aminoacyl-tRNA to ribosomes, peptide bond formation or translocation.