Rifabutin is an antibiotic used to treat tuberculosis and prevent and treat Mycobacterium avium complex, which works through inhibiting DNA-dependent RNA polymerase activity in susceptible cells.

Geldanamycin is a natural existing HSP90 inhibitor with Kd of 1.2 μM.

Rifampicin is a bacterial RNA polymerase inhibitor used in the treatment of bacterial infections.

Rifaximin is an RNA synthesis inhibitor by binding the β subunit of the bacterial DNA-dependent RNA polymerase, used to treat traveler's diarrhea caused by certain bacteria.