InterPro domain: IPR012293

Prokaryotes contain a single RNA polymerase (RNAP) that is responsible for the transcription of all genes, while eukaryotes have three classes of RNAPs (I-III) with specific transcriptional roles. In eukaryotes, the RPB6 subunit (also known as RPABC2) is common to all three polymerases. RPB6 is involved in the initiation of transcription. Bacterial DNA-dependent RNAP contains a small subunit termed omega, where the complete RNAP composition is beta'-beta-alpha(I)-alpha(II)-omega. The bacterial omega subunit is homologous in sequence and structure to the eukaryotic RPB6 subunit; they also have similar functional roles, being able to promote RNA polymerase assembly, possibly through a latching mechanism [ 1 ].

1. Bacterial RNA polymerase subunit omega and eukaryotic RNA polymerase subunit RPB6 are sequence, structural, and functional homologs and promote RNA polymerase assembly. Proc. Natl. Acad. Sci. U.S.A. 98, 892-7