DNA-directed RNA polymerase beta subunit (bacterial) (RNA polymerase β subunit)

The DNA-directed RNA polymerase beta subunit (encoded by rpoB) is an essential bacterial enzyme responsible for catalyzing the transcription of DNA into RNA. Rifampicin exerts its antibacterial activity by binding to the beta subunit of bacterial RNA polymerase, specifically in the DNA/RNA channel. This binding blocks RNA chain elongation after the initiation step, preventing the synthesis of bacterial proteins crucial for survival. Resistance to rifampicin typically emerges through mutations in the rpoB gene, particularly in the rifampicin resistance-determining region, which reduce drug binding affinity. Rifampicin does not affect mammalian RNA polymerase, contributing to its selectivity for bacterial pathogens.

Other names

rpoBBacterial RNA polymeraseDNA-dependent RNA polymerase β subunitRNAP β subunit

Inhibits bacterial DNA-dependent RNA polymerase by binding to its beta subunit, blocking RNA chain elongation and thus impeding bacterial RNA and protein synthesis (steric-occlusion mechanism)