The antibiotic rifampicin (Rifamycin B) inhibits transcription by:
A) binding the promoter to block association of RNA polymerase with the template.
B) binding RNA polymerase B_subunit to block transcription initiation.
C) binding sigma factor, thereby altering promoter specificity.
D) promoting spontaneous hydrolysis of newly synthesized phosphodiester bonds.
E) inhibiting translation, which is required for coupled transcription/translation in prokaryotes.

Question

Quizplus · Accepted Answer

Rifampicin (Rifamycin B) binds to the β subunit of bacterial RNA polymerase and thereby inhibits transcription initiation. As RNA polymerase binds to the promoter, it undergoes a conformational change, which is blocked by rifampicin bound to the β subunit. Other options mentioned are incorrect as rifampicin does not directly affect the promoter sequence, sigma factor, or translation.

The Antibiotic Rifampicin (Rifamycin B) Inhibits Transcription By