EFFECT OF DNA-INTERACTING DRUGS ON PHAGE T7 RNA-POLYMERASE

9-Aminoacridine carboxamide derivatives studied here form with DNA int ercalative complexes which differ in the kinetics of dissociation. Inh ibition of total RNA synthesis catalyzed by phage T7 and Escherichia c oli DNA-dependent RNA polymerases correlates with the formation of slo wly dissociating acridine-DNA complex of time constant of 0.4-2.3 s. T heir effect on RNA synthesis is compared with other ligands which form with DNA stable complexes of different steric properties. T7 RNA poly merase is more sensitive to distamycin A and netropsin than the E. col i enzyme while less sensitive to actinomycin D. Actinomycin induces te rminations in the transcript synthesized by T7 RNA polymerase. Despite low dissociation rates of DNA complexes with acridines and pyrrole an tibiotics no drug dependent terminations are observed with these ligan ds.