Which of the following drugs acts by
inhibiting the transcription of DNA to
RNA?
a) Rifampicin
b) Nitrofurantoin
c) Ciprofloxacin
d) Novobiocin
Correct Answer - A
Ans: A. Rifampicin
Overall inhibition of RNA synthesis by rifampicin is caused by a
destabilizing effect on the binding of the intermediate
oligonucleotides to the active enzyme-DNA complex.
Rifampicin itself can only interact specifically with RNA polymerase
if the enzyme is free or in a binary complex with DNA.
Ref: Rifampicin inhibition of RNA synthesis by destabilisation of DNA-RNA polymerase-oligonucleotide-complexes. - PMC