Citrocin is a potent inhibitor of bacterial RNA polymerase (RNAP). It exhibits significant inhibitory effects on Escherichia coli RNA polymerase, with a MIC range of 16–125 μM. Citrocin specifically binds to RNA polymerase, inhibiting its activity and thus blocking the bacterial transcription process. It predominantly enters cells through the inner membrane protein SbmA. Citrocin holds potential for research on infections caused by Gram-negative bacteria, such as enterohemorrhagic E. coli.