sigma factor activity

GO:0016987

Sigma factors act as the promoter specificity subunit of eubacterial and plant plastid multisubunit RNA polymerases, whose core subunit composition is often described as alpha(2)-beta-beta-prime. Although sigma does not bind DNA on its own, when combined with the core to form the holoenzyme, the sigma factor binds specifically to promoter elements. The sigma subunit is released once elongation begins.

DNA-dependent RNA polymerase promoter selection factor

sigma transcription factor

core DNA-dependent RNA polymerase binding promoter specificity activity

krc

2010-08-11T04:12:24Z

molecular_function

GO:0016987

bacterial sigma factor activity

plastid sigma factor activity

promoter selection factor activity

GO:0000996

GO:0001053