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MhpR DNA-binding transcriptional activator

Synonyms: MhpR-3HPP, MhpR-3-(2,3-dihydroxyphenyl)propionate [DHPP], MhpR
MhpR, hydroxyphenylpropionate regulator, participates in controlling the expression of several genes involved in degradation of phenylpropionate (PP) [2, 3] MhpR is able to bind to its DNA-binding site even in the absence of inducer; however, increasing concentrations of inducer improve the binding strength of MhpR. 3-(2,3-Dihydroxyphenyl)propionate (DHPP) and 3-hydroxyphenylpropionate (3HPP), two intermediates of the metabolic pathways, are the principal inducers of MhpR. The third inducer, phenylpropionate (PP), acts synergistically with DHPP and 3HPP [1, 2]
This protein, which belongs to the IclR family of transcriptional regulators, has a helix-turn-helix motif to bind DNA in its N-terminal domain and a 22-residue motif, specific to an IclR subfamily, in its C-terminal domain [3]
MhpR is necessary to recruit CRP to the regulatory region of the mhp operon, where both proteins activate transcription [2]
The mhpR gene, which is located downstream of the genes it regulates and in the opposite direction, appears to be expressed constitutively [2]
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Transcription factor      
TF conformation(s):
Name Conformation Type TF-Effector Interaction Type Apo/Holo Conformation Evidence (Confirmed, Strong, Weak) References
MhpR Non-Functional   Apo [BPP], [GEA], [IPI] [1]
MhpR-3-(2,3-dihydroxyphenyl)propionate [DHPP] Functional Allosteric Holo [BPP], [GEA], [IPI] [1]
MhpR-3HPP Functional Allosteric Holo [BPP], [GEA], [IPI] [1]
Evolutionary Family: IclR
Sensing class: Sensing external and internal signals
Connectivity class: Local Regulator
Gene name: mhpR
  Genome position: 367587-368420
  Length: 834 bp / 277 aa
Operon name: mhpR-lacI
TU(s) encoding the TF:
Transcription unit        Promoter

Regulated gene(s) mhpA, mhpB, mhpC, mhpD, mhpE, mhpF
Multifun term(s) of regulated gene(s) MultiFun Term (List of genes associated to the multifun term)
carbon compounds (5)
fatty acids (1)
Regulated operon(s) mhpABCDFE
First gene in the operon(s) mhpA
Simple and complex regulons CRP,MhpR
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
  MhpR-3HPP activator mhpAp Sigma70 -58.0 -150.0 mhpA, mhpB, mhpC, mhpD, mhpF, mhpE
368454 368468 [BCE], [GEA], [HIBSCS], [SM] [2]

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


 [BPP] Binding of purified proteins

 [GEA] Gene expression analysis

 [IPI] Inferred from physical interaction

 [BCE] Binding of cellular extracts

 [HIBSCS] Human inference based on similarity to consensus sequences

 [SM] Site mutation


 [1] Manso I., Torres B., Andreu JM., Menendez M., Rivas G., Alfonso C., Diaz E., Garcia JL., Galan B., 2009, 3-Hydroxyphenylpropionate and phenylpropionate are synergistic activators of the MhpR transcriptional regulator from Escherichia coli., J Biol Chem. 284(32):21218-28

 [2] Torres B., Porras G., Garcia JL., Diaz E., 2003, Regulation of the mhp cluster responsible for 3-(3-hydroxyphenyl) propionic acid degradation in escherichia coli., J Biol Chem. 278(30):27575-85.

 [3] Ferrandez A., Garcia JL., Diaz E., 1997, Genetic characterization and expression in heterologous hosts of the 3-(3-hydroxyphenyl)propionate catabolic pathway of Escherichia coli K-12., J Bacteriol. 179(8):2573-81