Protein Family Models

Region 4 of sigma-70 like sigma-factors are involved in binding to the -35 promoter element via a helix-turn-helix motif [1]. Due to the way Pfam works, the threshold has been set artificially high to prevent overlaps with other helix-turn-helix families. Therefore there are many false negatives. [1]. 11931761. Structure of the bacterial RNA polymerase promoter specificity sigma subunit. Campbell EA, Muzzin O, Chlenov M, Sun JL, Olson CA, Weinman O, Trester-Zedlitz ML, Darst SA;. Mol Cell 2002;9:527-539. (from Pfam)

Date:

2024-10-16

This HMM hits a core region shared by multiple sigma factors, interchangeable subunits that complete the RNA polymerase holoenzyme and allow transcription to start. In E. coli K-12 alone, this HMM hits RpoD (sigma-70), RpoH (sigma-32), FliA (sigma-28), FecI (sigma-19), RpoS, and RpoE.

Date:

2024-10-16

Region 3 forms a discrete compact three helical domain within the sigma-factor. Region is not normally involved in the recognition of promoter DNA, but as some specific bacterial promoters containing an extended -10 promoter element, residues within region 3 play an important role. Region 3 primarily is involved in binding the core RNA polymerase in the holoenzyme [1]. [1]. 11931761. Structure of the bacterial RNA polymerase promoter specificity sigma subunit. Campbell EA, Muzzin O, Chlenov M, Sun JL, Olson CA, Weinman O, Trester-Zedlitz ML, Darst SA;. Mol Cell 2002;9:527-539. (from Pfam)

Date:

2024-10-16

RNA polymerase sporulation sigma factor SigG is responsible for the expression of sporulation specific genes in the forespore

Date:

2017-12-07

This group of similar sigma-70 factors includes clades found in Bacilli (including the sporulation factors SigF:TIGR02885 and SigG:TIGR02850 as well as SigB:TIGR02941), and the high GC gram positive bacteria (Actinobacteria) where a variable number of them are found depending on the lineage.

Date:

2024-05-30

This model encompasses all varieties of the sigma-70 type sigma factors including the ECF subfamily. A number of sigma factors have names with a different number than 70 (i.e. sigma-38), but in fact, all except for the Sigma-54 family (TIGR02395) are included within this family. Several PFAM models hit segments of these sequences including Sigma-70 region 2 (PF04542) and Sigma-70, region 4 (PF04545), but not always above their respective trusted cutoffs.

Date:

2024-06-27

Members of this family comprise the Firmicutes lineage endospore formation-specific sigma factor SigG. It is also desginated stage III sporulation protein G (SpoIIIG). This protein is rather closely related to sigma-F (SpoIIAC), another sporulation sigma factor.

Gene:

sigG

Date:

2024-05-30

Sigma factor binds with the catalytic core of RNA polymerase to produce the holoenzyme and directs bacterial core RNA polymerase to specific promoter elements to initiate transcription; this factor is involved in the transcription of small acid-soluble proteins involved in protecting the forespore chromatin

Gene:

sigG

Date:

2020-10-26