What is the mechanism of action of rifamycins?

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Multiple Choice

What is the mechanism of action of rifamycins?

Rifamycins work by shutting down bacterial transcription. They bind to the beta subunit of DNA-dependent RNA polymerase (the enzyme that reads DNA to make RNA) and prevent the initiation and elongation of RNA chains. Because transcription is essential for making all proteins, this blocks RNA synthesis and kills actively growing bacteria. This mechanism is distinct from other antibiotic actions like inhibiting ribosomal protein synthesis, cell wall construction, or folate metabolism, which is why rifamycins act specifically on bacterial RNA polymerase. Resistance typically comes from mutations in the RNA polymerase beta subunit that reduce drug binding.

Rifamycins work by shutting down bacterial transcription. They bind to the beta subunit of DNA-dependent RNA polymerase (the enzyme that reads DNA to make RNA) and prevent the initiation and elongation of RNA chains. Because transcription is essential for making all proteins, this blocks RNA synthesis and kills actively growing bacteria. This mechanism is distinct from other antibiotic actions like inhibiting ribosomal protein synthesis, cell wall construction, or folate metabolism, which is why rifamycins act specifically on bacterial RNA polymerase. Resistance typically comes from mutations in the RNA polymerase beta subunit that reduce drug binding.

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