Refereed journal article or data article (A1)

Revealing secrets of the enigmatic omega subunit of bacterial RNA polymerase

List of Authors: Juha Kurkela, Julia Fredman, Tiina A Salminen, Taina Tyystjärvi

Publisher: John Wiley & Sons Ltd

Publication year: 2020

Journal: Molecular Microbiology

Journal acronym: Mol. Microbiol.

Volume number: 115

Issue number: 1

Number of pages: 11

ISSN: 0950-382X

eISSN: 1365-2958



The conserved omega (ω) subunit of RNA polymerase (RNAP) is the only nonessential subunit of bacterial RNAP core. The small ω subunit (7 kDa–11.5 kDa) contains three conserved α helices, and helices α2 and α3 contain five fully conserved amino acids of ω. Four conserved amino acids stabilize the correct folding of the ω subunit and one is located in the vicinity of the β′ subunit of RNAP. Otherwise ω shows high vari- ation between bacterial taxa, and although the main interaction partner of ω is always β′, many interactions are taxon-specific. ω-less strains show pleiotropic phenotypes, and based on in vivo and in vitro results, a few roles for the ω subunits have been described. Interactions of the ω subunit with the β′ subunit are important for the RNAP core assembly and integrity. In addition, the ω subunit plays a role in promoter selection, as ω-less RNAP cores recruit fewer primary σ factors and more alternative σ factors than intact RNAP cores in many species. Furthermore, the promoter selec- tion of an ω-less RNAP holoenzyme bearing the primary σ factor seems to differ from that of an intact RNAP holoenzyme.

Last updated on 2021-24-06 at 08:29