Inhibition of RNA polymerase activity by the Escherichia coli protein biosynthesis elongation factor Ts

The transcribing activity of DNA-dependent RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) from Escherichia coli is inhibited in vitro by addition of preparations of elongation factor Ts purified to homogeneity. The inhibitory activity of elongation factor Ts on the RNA polymerase activity and the enzymatic activity of elongation factor Ts show the same temperature sensitivity. The extent of inhibition is strongly dependent on the template used for transcription. A mechanism for the control of RNA synthesis in vivo based on this inhibition found in vitro is proposed.