EUKARYOTIC PROTEIN-SYNTHESIS - AN IN-VITRO ANALYSIS

The general mechanism of eukaryotic protein synthesis is discussed based upon the accumulation of considerable data from in vitro assays of either purified factors or reconstituted systems. Recent evidence suggests that there are more factors/proteins that participate in this process than previously thought. These new discoveries however, do not alter 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 the phosphorylation state of eIF-2 alpha and a new mechanistic interpretation 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.