Further Evidence that Elongation Factor 1 Remains Bound to Ribosomes during Peptide Chain Elongation

Abstract

Three types of experiments are described which indicate that the binding sites for elongation factor 1 (EF-1) and elongation factor 2 (EF-2) on ascites cell ribosomes are not identical and perhaps not even overlapping. The experimental evidence presented includes direct competitive binding of labeled elongation factors to ribosomes and the influence of pokeweed antiviral protein and Escherichia coli anti-L7/L12 proteins on the binding and function of the 2 factors. EF-1.beta. from Artemia salina does not function in displacing EF-1 from mouse ascites tumor cell ribosomes. The recently proposed model that EF-1 remains bound to the ribosome during the peptide chain elongation cycle was supported.