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ArsR DNA-binding transcriptional repressor

Synonyms: ArsR-arsenite, ArsR, ArsR-antimonite ion
Summary:
ArsR negatively controls the expression of the genes involved in arsenical and antimonite metals resistance whose expression is induced in the presence of these metals [2, 4, 5, 6] This protein is autoregulated; arsR is the first gene in the arsRBC operon that it regulates [6] ArsR belongs to the ArsR/SmtB family of transcriptional regulators that respond to a variety of metals [1] ArsR has a helix-turn-helix motif for DNA binding, a metal-binding site [3] and a dimerization domain [7] The inducer-binding sites for the members of this family appear to have arisen by convergent evolution [] In ArsR the inducer-binding site contains three cysteine residues that bind arsenite and antimonite specifically and with high affinity [3] Dimerization of ArsR is required for DNA binding and its ability to act as a transcriptional repressor [7] The dimer recognizes and binds to a 12-2-12 inverted repeat [1, 4] but the binding of arsenic or antimonite to ArsR causes a conformational change in it, leading to dissociation from DNA and hence derepression [] The chromosomal ArsR shows 75% identity to ArsR of Escherichia coli plasmid R773 and 26% identity to staphylococcal plasmid pI258 and pSX267 ArsR proteins [5] ArsR when overexpressed has the capacity to remove arsenic species from contaminated water [] ArsR: homologous to "arsenate inducibility regulator" [6] Review: [1] Read more >


Transcription factor      
TF conformation(s):
Name Conformation Type TF-Effector Interaction Type Apo/Holo Conformation Evidence (Confirmed, Strong, Weak) References
ArsR Functional   Apo [APPHINH], [HIFS], [IEP] [1], [2], [3], [4]
ArsR-antimonite ion Non-Functional Allosteric Holo nd nd
ArsR-arsenite Non-Functional Allosteric Holo nd nd
Evolutionary Family: ArsR
Sensing class: External sensing using transported metabolites
Connectivity class: Local Regulator
Gene name: arsR
  Genome position: 3648528-3648881
  Length: 354 bp / 117 aa
Operon name: arsRBC
TU(s) encoding the TF:
Transcription unit        Promoter
arsRBC
arsRp


Regulon       
Regulated gene(s) arsB, arsC, arsR
Multifun term(s) of regulated gene(s) MultiFun Term (List of genes associated to the multifun term)
detoxification (2)
The Arsenite-Antimonite (Ars) Efflux Family (1)
membrane (1)
Transcription related (1)
repressor (1)
Read more >
Regulated operon(s) arsRBC
First gene in the operon(s) arsR
Simple and complex regulons ArsR
Simple and complex regulatory phrases Regulatory phrase (List of promoters regulated by the phrase)
[ArsR,-](1)


Transcription factor regulation    


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
  ArsR repressor arsRp Sigma70 -41.5 -57.5 arsR, arsB, arsC
acacattcgtTAAGTCATATATGTTTTTGACTTAtccgcttcga
3648459 3648482 [AIBSCS], [BPP], [GEA] [1], [2], [4]


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


Evidence    

 [APPHINH] Assay of protein purified to homogeneity from its native host

 [HIFS] Human inference of function from sequence

 [IEP] Inferred from expression pattern

 [AIBSCS] Automated inference based on similarity to consensus sequences

 [BPP] Binding of purified proteins

 [GEA] Gene expression analysis



Reference(s)    

 [1] Busenlehner LS., Pennella MA., Giedroc DP., 2003, The SmtB/ArsR family of metalloregulatory transcriptional repressors: Structural insights into prokaryotic metal resistance., FEMS Microbiol Rev 27(2-3):131-43

 [2] Cai J., DuBow MS., 1996, Expression of the Escherichia coli chromosomal ars operon., Can J Microbiol 42(7):662-71

 [3] Shi W., Wu J., Rosen BP., 1994, Identification of a putative metal binding site in a new family of metalloregulatory proteins., J Biol Chem 269(31):19826-9

 [4] Xu C., Shi W., Rosen BP., 1996, The chromosomal arsR gene of Escherichia coli encodes a trans-acting metalloregulatory protein., J Biol Chem 271(5):2427-32

 [5] Carlin A., Shi W., Dey S., Rosen BP., 1995, The ars operon of Escherichia coli confers arsenical and antimonial resistance., J Bacteriol 177(4):981-6

 [6] Diorio C., Cai J., Marmor J., Shinder R., DuBow MS., 1995, An Escherichia coli chromosomal ars operon homolog is functional in arsenic detoxification and is conserved in gram-negative bacteria., J Bacteriol 177(8):2050-6

 [7] Xu C., Rosen BP., 1997, Dimerization is essential for DNA binding and repression by the ArsR metalloregulatory protein of Escherichia coli., J Biol Chem 272(25):15734-8



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