Purification and properties of DNA-dependent RNA polymerase from Mycobacterium tuberculosis H₃₇R_v

Abstract

RNA polymerase (nucleosidetriphosphate : RNA nucleotidyltransferase (DNA-dependent), EC 2.7.7.6) was purified approximately 200 fold from Mycobacterium tuberculosis H₃₇R_v cells. The purified enzyme has a molecular weight of about 330 000-350 000 and is composed of four subunits. The subunits β', β and σ have molecular weights different from those of Escherichia coli polymerase; the fourth, α subunit has a similar weight. The purified enzyme is a thousand-fold more sensitive to rifampicin, a potent antitubercular drug, than the E. coli RNA polymerase, probably because of the difference in the β subunits. This, with other data presented in this paper, indicate that the RNA polymerase of M. tuberculosis differs in its properties from that of E. coli.