EUKARYOTIC PROTEIN-SYNTHESIS - AN IN-VITRO ANALYSIS

The general mechanism of eukaryotic protein synthesis is discussed bas ed upon the accumulation of considerable data from in vitro assays of either purified factors or reconstituted systems. Recent evidence sugg ests that there are more factors/proteins that participate in this pro cess than previously thought. These new discoveries however, do not al ter the apparent function of the previously characterized factors, so that the general guidelines for understanding how Met-tRNA(i) and mRNA are correctly positioned on the 40S subunit have not changed. The two 'new' observations are the ability of a 67 kDa protein to influence t he phosphorylation state of eIF-2 alpha and a new mechanistic interpre tation of the utilization of the mRNA specific factors (eIF-4A, eIF-4B , eIF-4F) which would suggest that eIF-4A may not bind to mRNA except as a subunit of eIF-4F.