Bacterial DNA-directed RNA polymerase subunit beta (RpoB)

Bacterial DNA-directed RNA polymerase subunit beta (RpoB) is a fundamental component of the multisubunit enzyme complex responsible for transcribing DNA into RNA [3, 5]. As a core subunit, it contains key elements of the enzyme's active center and is essential for the synthesis of all types of bacterial RNA, including mRNA, tRNA, and rRNA [3, 10]. RpoB is a highly validated therapeutic target for the rifamycin class of antibiotics, such as rifampicin and rifabutin, which are cornerstones in the treatment of tuberculosis and other serious bacterial infections [2, 11]. These drugs bind to a specific pocket on the beta-subunit and physically block the elongation of the nascent RNA chain, leading to bacterial cell death [10, 18]. Because of its critical role in bacterial survival and its structural divergence from eukaryotic RNA polymerases, it offers a high degree of selectivity for antimicrobial therapy [18, 19]. However, the rapid emergence of resistance through point mutations in the rpoB gene remains a significant clinical challenge and serves as a primary biomarker for diagnosing drug-resistant strains [6, 14]. Additionally, drugs targeting this subunit, particularly rifampicin, are known for inducing hepatic enzymes, which necessitates careful management of drug-drug interactions [11, 20].

Other names

RNA polymerase subunit betaDNA-directed RNA polymerase subunit betarpoB gene productRNAP beta subunitBacterial RNA polymerase beta subunit

Rifamycins bind to a highly conserved pocket on the beta subunit of the bacterial RNA polymerase, sterically blocking the path of the nascent RNA transcript once it reaches a length of 2-3 nucleotides, thereby inhibiting RNA chain elongation and halting transcription [10, 18, 20].