- sigma factor activity
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.
- obsolete Sigma-E factor negative regulation complex
OBSOLETE. A protein complex consisting of RseA, RseB and RpoE. It form the inactive form of the sigma-E transcription factor. In response to stress, outer membrane proteins accumulate in the periplasm and activate cleavage of RseA periplasmic domain by DegS, triggering a proteolytic cascade that frees sigma-E to activate gene expression. RseB binding to RseA prevents activated DegS from cleaving RseA. Sigma-E-mediated envelope stress response is the major pathway to ensure homeostasis in the envelope compartment of the cell.
- antisigma factor binding
Binding to an antisigma factor, a factor which inhibits the ability of the sigma factor to function as a transcriptional initiator.
- bacterial-type RNA polymerase holo enzyme binding
Binding to a component of the basal transcription machinery which is composed of a bacterial-type RNA polymerase core enzyme and a sigma factor, the minimal set of factors required for formation of the preinitiation complex (PIC) by a bacterial-type RNA polymerase.
- cytosolic DNA-directed RNA polymerase complex
The eubacterial DNA-directed RNA polymerase is a multisubunit complex with a core composed of the essential subunits beta-prime, beta, and two copies of alpha and a fifth nonessential subunit called omega. An additional subunit, a sigma factor, is required for promoter recognition and specificity.
- plastid-encoded plastid RNA polymerase complex
An RNA polymerase complex containing polypeptides encoded by the plastid genome. Plastid-encoded DNA-directed RNA polymerases resemble eubacterial multisubunit RNA polymerases, with a core composed of alpha, beta, and beta-prime subunits. Some forms contain multiple additional subunits. An additional sigma factor subunit is required for promoter recognition.
- plastid-encoded plastid RNA polymerase complex A
A plastid-encoded DNA-directed RNA polymerase complex that resembles eubacterial multisubunit RNA polymerases, with a core composed of alpha, beta, and beta-prime subunits. An additional subunit, a sigma factor, is required for promoter recognition. PEP-A is generated from the PEP-B form during chloroplast maturation to generate a complex composed of at least thirteen polypeptides that is not sensitive to the antibiotic rifampicin, like its precursor form the PEP-B complex.