DNA-directed RNA polymerase subunit beta (RpoB) (RpoB)

DNA-directed RNA polymerase subunit beta (RpoB) is a critical enzyme in Mycobacterium tuberculosis responsible for catalyzing the transcription of DNA into RNA (Source: UniProt P9WGY9). As a core component of the RNA polymerase holoenzyme, it plays a fundamental role in bacterial gene expression, growth, and survival. RpoB is the primary pharmacological target for the rifamycin class of antibiotics, such as rifampicin, which remains a cornerstone of first-line tuberculosis treatment (Source: PubMed: 24930981). These drugs bind to a highly conserved pocket within the beta subunit near the active site, physically blocking the elongation of the nascent RNA chain shortly after initiation. Mutations within the rpoB gene, specifically clustered in the 81-base pair rifampicin resistance-determining region (RRDR), are responsible for approximately 95% of rifampicin resistance in clinical isolates (Source: PubMed: 30209060). Because rifampicin resistance is often a surrogate marker for multi-drug resistant tuberculosis (MDR-TB), RpoB is a focal point for both therapeutic intervention and diagnostic molecular testing.

Other names

RNA polymerase beta subunitDNA-directed RNA polymerase subunit betaBeta subunit of RNA polymeraserpoB

Inhibition of DNA-directed RNA polymerase by binding to the beta subunit at a site adjacent to the active center, which sterically blocks the path of the nascent RNA transcript once it reaches a length of 2-3 nucleotides, thereby preventing RNA elongation (Source: DrugBank DB01086; PubMed: 11586045).