DNA-directed RNA polymerase subunit beta (Mycobacterium tuberculosis) (rpoB)

The DNA-directed RNA polymerase subunit beta (RpoB) is one of the core subunits of the multisubunit bacterial DNA-dependent RNA polymerase enzyme complex, essential for the transcription of DNA into RNA in Mycobacterium tuberculosis. Functional RNA polymerase consists of the core enzyme (α2ββ′ω) and a sigma factor; the beta subunit, encoded by the rpoB gene, forms a catalytic and structural core for nucleotide polymerization[1][8]. RpoB is the principal target for rifampicin, a first-line anti-tuberculosis agent, which binds near its active site and inhibits RNA synthesis by steric hindrance; mutations in rpoB account for most cases of rifampicin-resistant M. tuberculosis[6][8]. Structural studies have shown unique features in the Mycobacterium genus, offering additional avenues for drug development beyond rifamycins[6]. The beta subunit has no known non-essential or redundant function in M. tuberculosis and is indispensable for bacterial viability and virulence[8]. Detection of rpoB mutations is widely used as a molecular biomarker for rapid identification of rifampicin-resistant tuberculosis, which is of high clinical importance. Key sources supporting the above include UniProt entry A5U052, detailing RpoB structure, function, and drug interaction[8], as well as multiple structural and mechanistic studies illustrating its fundamental role in transcription and as an antimicrobial target[6].

Other names

RNA polymerase beta subunitRNAP betaRpoBDNA-dependent RNA polymerase subunit beta

Inhibition of RNA synthesis by binding the beta subunit and blocking RNA chain elongation (rifampicin and related drugs); Steric inhibition and allosteric modulation (different mechanisms for various non-rifampicin inhibitors)[6][8]