[Effect of oligoribonucleotides specifically bound by E. coli RNA-polymerase on DNA-dependent RNA synthesis]

It was shown previously that E. coli RNA-polymerase (EC 2.7.7.6) selectively binds certain fractions of penta- or hexaribonucleotides random mixtures (Knorre V. L., Vasilenko S. V., Salganik R. I., FEBS Lett., 30, 229, 1973). The data obtained demonstrate that such oligoribonucleotides compete with DNA for the RNA polymerase active centre and inhibit DNA dependent RNA synthesis catalyzed by the enzyme. These properties are absent in tri- and tetraribonucleotides which cannot be bound by RNA polymerase. The inhibitory action of the pentaribonucleotides was higher when they had been added prior to DNA to the mixture containing RNA polymerase.