Sigma54_AID |
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PFAM accession number: | PF00309 |
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Interpro abstract (IPR000394): | Sigma factors [ (PUBMED:3052291) ] are bacterial transcription initiation factors that promote the attachment of the core RNA polymerase to specific initiation sites and are then released. They alter the specificity of promoter recognition. 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. The sigma-70 family has many different sigma factors (see the relevant entry IPR000943 ). The sigma-54 family consists exclusively of sigma-54 factor [ (PUBMED:2517036) (PUBMED:7934866) ] required for the transcription of promoters that have a characteristic -24 and -12 consensus recognition element but which are devoid of the typical -10, -35 sequences recognised by the major sigma factors. The sigma-54 factor is also characterised by its interaction with ATP-dependent positive regulatory proteins that bind to upstream activating sequences. Structurally sigma-54 factors consist of three distinct regions:
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GO function: | DNA-binding transcription activator activity (GO:0001216), sigma factor activity (GO:0016987) |
This is a PFAM domain. For full annotation and more information, please see the PFAM entry Sigma54_AID