What is the mechanism of action of rifampin?

Rifampin exerts its therapeutic effects by blocking mRNA transcription through the inhibition of bacterial RNA polymerase, specifically the DNA-dependent RNA polymerase enzyme. By binding to the β-subunit of this enzyme, rifampin prevents the synthesis of RNA from the DNA template, effectively halting the process of transcription. This action is essential for the proliferation of bacteria, making rifampin particularly effective against organisms like Mycobacterium tuberculosis.

In contrast to the other options, the mechanism of rifampin is distinctly centered on inhibiting transcription rather than affecting translation or peptidoglycan synthesis. Other mechanisms, such as inhibiting peptidyl transferase or binding to D-ala-D-ala, relate to different antibiotic classes, emphasizing the unique function of rifampin in managing bacterial infections.