Inhibition of Nucleic Acid Biosynthesis in Cell-free Systems of Escherichia coli B by Pluramycin

The effect of pluramycin on nucleic acid synthesis in cell-free systems of Escherichia coli B was investigated. DNA synthesis was a little more susceptible to pluramycin than RNA synthesis. DNA polymerase [EC 2.7.7.7] reaction was inhibited by pluramycin and the effect of pluramycin was independent from the stage of the reaction where the pluramycin was added. The inhibition was reversed by increasing the amount of template DNA but not by magnesium ion, deoxyribonucleoside triphosphates or the enzyme. Difference spectra of pluramycin were obtained by adding DNA, sRNA and synthetic polyribonucleotides. The growth-inhibitory effect of pluramycin against Mycoplasma mycoides var. mycoides was reduced by the addition of DNA. Thus, pluramycin was proved to bind with DNA and to inhibit DNA and RNA polymerase [EC 2.7.7.7 and 6] reactions.