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DhaR DNA-binding transcriptional dual regulator

Synonyms: DhaR-DhaK, DhaR
Summary:
Dihydroxyacetone Regulator, DhaR, is negatively autoregulated and coordinately activates transcription of the divergent dha operon (dhaKLM), which encodes three subunits of the dihydroxyacetone (DHA) kinase [1].
DhaR is inactivated when DnaK binds to the sensing domain of this regulator, in the absence of DHA [1]. Dephosphorylated DhaL (DhaL::ADP) is an antagonist of DhaK and also is able to form complexes with the sensing domain of DhaR. In the presence of DHA, DhaL::ADP displaces DhaK or blocks the association of the DhaK/DhaR complex and DhaR activates the transcription of the dha operon [1].
DhaR belongs to the family of bacterial enhancer-binding proteins which contain three domains: the sensing domain located in the N terminus, the central AAA+ domain, and the C-terminal domain, which contains a helix-turn-helix motif involved in the interaction with DNA. Although the C-terminal domain and the N-terminal domain from DhaR are similar to those of other members of this group, its central domain is not [1].
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Transcription factor      
TF conformation(s):
Name Conformation Type TF-Effector Interaction Type Apo/Holo Conformation Evidence (Confirmed, Strong, Weak) References
DhaR Functional   Apo [BPP], [IPI] [1]
DhaR-DhaK Non-Functional Allosteric Holo [BPP], [IPI] [1]
Evolutionary Family: EBP
Connectivity class: Local Regulator
Gene name: dhaR
  Genome position: 1251066-1252985
  Length: 1920 bp / 639 aa
Operon name: dhaR
TU(s) encoding the TF:
Transcription unit        Promoter
dhaR
dhaRp


Regulon       
Regulated gene(s) dhaK, dhaL, dhaM, dhaR
Multifun term(s) of regulated gene(s) MultiFun Term (List of genes associated to the multifun term)
carbon compounds (3)
Transcription related (1)
activator (1)
repressor (1)
two component regulatory systems (external signal) (1)
Regulated operon(s) dhaKLM, dhaR
First gene in the operon(s) dhaK, dhaR
Simple and complex regulons DhaR
Simple and complex regulatory phrases Regulatory phrase (List of promoters regulated by the phrase)


Transcription factor binding sites (TFBSs) arrangements       

  Functional conformation Function Promoter Sigma factor Central Rel-Pos Distance to first Gene Genes Sequence LeftPos RightPos Evidence (Confirmed, Strong, Weak) References
  DhaR activator dhaKp Sigma38 nd nd dhaK, dhaL, dhaM nd nd [GEA] [1]
  DhaR repressor dhaRp Sigma38 nd nd dhaR nd nd [GEA] [1]


Evolutionary conservation of regulatory elements    
     Note: Evolutionary conservation of regulatory interactions and promoters is limited to gammaproteobacteria.
Promoter-target gene evolutionary conservation


Evidence    

 [BPP] Binding of purified proteins

 [IPI] Inferred from physical interaction

 [GEA] Gene expression analysis



Reference(s)    

 [1] Bachler C., Schneider P., Bahler P., Lustig A., Erni B., 2005, Escherichia coli dihydroxyacetone kinase controls gene expression by binding to transcription factor DhaR., EMBO J. 24(2):283-93

 [2] Shi R., McDonald L., Cygler M., Ekiel I., 2014, Coiled-coil helix rotation selects repressing or activating state of transcriptional regulator DhaR., Structure. 22(3):478-87



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