Inhibition of the first phosphodiester bond formation catalyzed by Escherichia coli RNA polymerase in the presence of bovine seminal plasmin: promoter dependency

Abstract

Inhibition of the abortive initiation of transcription catalyzed by E. coli RNA polymerase has been studied here in the presence of bovine seminal plasmin. Seminal plasmin, which is known to be a stronger inhibitor than rifampicin binds at the same site as rifampicin to RNA polymerase. However, unlike rifampicin, seminal plasmin showed the inhibition of the formation of both the first and second phosphodiester bonds. We observed, in vitro, that the degree of inhibition of transcription was different at different promoters. Thus, the percent of inhibition of transcription initiation by seminal plasmin was much less at r-RNA promoters in comparison to that at the early promoters of bacteriophage T7.