STREPTOTHRICIN F, AN INHIBITOR OF PROTEIN SYNTHESIS WITH MISCODING ACTIVITY

Abstract

The effect of streptothricin F on macromolecular syntheses in intact cells and cell-free protein synthesis of E. coli was studied. The results indicate that protein synthesis is the primary site of inhibition by streptothricin F in growing E. coli cells. Cell-free polypeptide synthesis from E. coli directed by poly (U) was inhibited, while poly (A) and poly (C) directed polypeptide syntheses were both stimulated by the drug. Furthermore, streptothricin F caused misreading of translation of poly (U), poly (A) and poly (C) directed protein syntheses in E. coli systems. The extent of misreading by streptothricin F increases with increasing drug concentrations. The results are compared with those of other miscoding antibiotics. In rat liver extracts protein synthesis directed by poly (U) or endogenous mRNA was not inhibited.