InterPro : IPR000943

Name  RNA polymerase sigma-70 Short Name  RNA_pol_sigma70
Type  Domain Description  The bacterial core RNA polymerase complex, which consists of five subunits, is sufficient for transcription elongation and termination but is unable to initiate transcription. Transcription initiation from promoter elements requires a sixth, dissociable subunit called a sigma factor, which reversibly associates with the core RNA polymerase complex to form a holoenzyme []. RNA polymerase recruits alternative sigma factors as a means of switching on specific regulons. Most bacteria express a multiplicity of sigma factors. Two of these factors, sigma-70 (gene rpoD), generally known as the major or primary sigma factor, and sigma-54 (gene rpoN or ntrA) direct the transcription of a wide variety of genes. The other sigma factors, known as alternative sigma factors, are required for the transcription of specific subsets of genes.With regard to sequence similarity, sigma factors can be grouped into two classes, the sigma-54 and sigma-70 families. Sequence alignments of the sigma70 family members reveal four conserved regions that can be further divided into subregions eg. sub-region 2.2, which may be involved in the binding of the sigma factor to the core RNA polymerase; and sub-region 4.2, which seems to harbor a DNA-binding 'helix-turn-helix' motif involved in binding the conserved -35 region of promoters recognised by the major sigma factors [, ]. Each sigma2 domain is composed of a bundle of three alpha-helices that is virtually identical in all structures analyzed to date []. The second helix of this bundle is a major point for contact with a coiled-coil domain in the beta' subunit of the core RNA polymerase complex. The third helix of the bundle includes conserved residues along one face that are involved in DNA melting and in recognition of the -10 promoter element. The sigma3 domain, which is less conserved between members of the sigma70 family is also a three-helix domain, the first helix of which contains the residues implicated in contacting DNA upstream of extended -10 promoters. The sigma4, domain has two pairs of alpha helices; the carboxy-terminal pair forms a helix-turn-helix motif that contacts the promoter DNA in the region from -30 to -38.
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Sequence Features

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Proteins

InterPro protein domain ID --> Contigs

 

Other

1 Child Features

Id Name Short Name Type
IPR012760 RNA polymerase sigma factor RpoD, C-terminal RNA_pol_sigma_RpoD_C Domain

6 Contains

Id Name Short Name Type
IPR011991 Winged helix-turn-helix DNA-binding domain WHTH_DNA-bd_dom Domain
IPR013324 RNA polymerase sigma factor, region 3/4 RNA_pol_sigma_r3_r4 Domain
IPR013325 RNA polymerase sigma factor, region 2 RNA_pol_sigma_r2 Domain
IPR007627 RNA polymerase sigma-70 region 2 RNA_pol_sigma70_r2 Domain
IPR007630 RNA polymerase sigma-70 region 4 RNA_pol_sigma70_r4 Domain
IPR007624 RNA polymerase sigma-70 region 3 RNA_pol_sigma70_r3 Domain

11 Found In

Id Name Short Name Type
IPR012759 RNA polymerase sigma factor RpoH, proteobacteria RNA_pol_sigma_RpoH_proteobac Family
IPR016371 RNA polymerase sigma-H factor RNA_pol_sigma-H_factor Family
IPR014218 RNA polymerase sigma-H type RNA_pol_sigma-H Family
IPR016263 RNA polymerase sporulation-specific sigma factor, SigK/SigE RNA_pol_sigma-SigE/K Family
IPR014200 RNA polymerase sigma-E type RNA_pol_sigma-E Family
IPR014209 RNA polymerase sigma-K type RNA_pol_sigma-K Family
IPR016262 RNA polymerase sigma factor, SigB/SigC/SigD, plastid RNA_pol_sigma_SigB/C/D_plastid Family
IPR012845 RNA polymerase sigma factor, FliA/WhiG RNA_pol_sigma_FliA_WhiG Family
IPR014322 RNA polymerase sigma-B/F/G type RNA_pol_sigma-B/F/G Family
IPR012761 RNApolymerase sigma factor RpoS RNA_pol_sigma_RpoS Family
IPR017848 RNA polymerase sigma factor, RpoD-like, cyanobacteria RNA_pol_sigma_RpoD_cyanobac Family

1 Parent Features

Id Name Short Name Type
IPR014284 RNA polymerase sigma-70 like domain RNA_pol_sigma-70_dom Domain

4 Publications

First Author Title Year Journal Volume Pages
Helmann JD Structure and function of bacterial sigma factors. 1988 Annu Rev Biochem 57 839-72
Lonetto M The sigma 70 family: sequence conservation and evolutionary relationships. 1992 J Bacteriol 174 3843-9
Gribskov M Sigma factors from E. coli, B. subtilis, phage SP01, and phage T4 are homologous proteins. 1986 Nucleic Acids Res 14 6745-63
Paget MS The sigma70 family of sigma factors. 2003 Genome Biol 4 203



To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)