DNA-directed RNA polymerase beta subunit

DNA-directed RNA polymerase beta subunit is a core component of the bacterial multisubunit RNA polymerase (RNAP) complex, encoded by the rpoB gene[1][4]. It plays a crucial structural and catalytic role in the transcription of DNA into RNA within bacteria[1][4][5]. The beta subunit, together with the beta-prime subunit, forms the active center of the enzyme, where ribonucleotides are selected and incorporated into the growing RNA chain[1][5][6]. This beta subunit contains a double-psi-beta-barrel (DPBB) domain that interacts with nucleotides and contributes essential residues to the catalytic active site[1][6]. The conformation and dynamics of the beta subunit are essential during transcription elongation, pausing, and termination[1]. Rifampicin and related antibiotics specifically target this beta subunit, binding to it and inhibiting RNA synthesis, which makes it a central target in the treatment of various bacterial infections, most notably tuberculosis[1][4]. Mutations in the rpoB gene are a primary mechanism by which bacteria develop resistance to rifampicin, which is both a clinical challenge and a diagnostic biomarker[1][4]. The beta subunit is absent in archaea and eukaryotes in the same form, but structural and functional homology exists between bacterial and eukaryotic RNA polymerase subunits[3][6].

Other names

RNA polymerase beta subunitRNAP beta subunitrpoB gene productDNA-dependent RNA polymerase beta subunit

Inhibition of RNA synthesis by rifampicin-family drugs involves binding to the beta subunit and blocking the RNA exit channel, thereby preventing the elongation of the nascent RNA chain.