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ArsR DNA-binding transcriptional repressor

Synonyms: ArsR-arsenite, ArsR-antimonite, ArsR
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 |CITS:[7860609][7721697][8764681][8576202]|. This protein is autoregulated; arsR is the first gene in the arsRBC operon that it regulates |CITS:[7721697]|.
ArsR belongs to the ArsR/SmtB family of transcriptional regulators that respond to a variety of metals |CITS:[12829264]|. ArsR has a helix-turn-helix motif for DNA binding, a metal-binding site |CITS:[8051064]|, and a dimerization domain |CITS:[9188467]|. The inducer-binding sites for the members of this family appear to have arisen by convergent evolution |CITS:[17897948]|. In ArsR the inducer-binding site contains three cysteine residues that bind arsenite and antimonite specifically and with high affinity |CITS:[8051064][8621591]|.
Dimerization of ArsR is required for DNA binding and its ability to act as a transcriptional repressor |CITS:[9188467]|. The dimer recognizes and binds to a 12-2-12 inverted repeat |CITS:[12829264][8576202]|, but the binding of arsenic or antimonite to ArsR causes a conformational change in it, leading to dissociation from DNA and hence derepression |CITS:[8621591]|.
The chromosomal ArsR shows 75% identity to ArsR of Escherichia coli plasmid R773 and 26% identity to staphylococcal plasmid pI258 and pSX267 ArsR proteins |CITS:[7860609]|.
ArsR when overexpressed has the capacity to remove arsenic species from contaminated water |CITS:[ 15294789] [23484908]|.
ArsR: homologous to arsenate inducibility regulator |CITS:[7721697]|.
Review: |CITS:[12829264]|. 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 [BPP], [GEA], [IPI], [SM] [1]
ArsR-antimonite Non-Functional Allosteric Holo [BPP], [GEA], [IPI], [SM] [1]
ArsR-arsenite Non-Functional Allosteric Holo [BPP], [GEA], [IPI], [SM] [1]
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 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] [2], [3], [4]


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

 [GEA] Gene expression analysis

 [IPI] Inferred from physical interaction

 [SM] Site mutation

 [AIBSCS] Automated inference based on similarity to consensus sequences



Reference(s)    

 [1] Shi W., Dong J., Scott RA., Ksenzenko MY., Rosen BP., 1996, The role of arsenic-thiol interactions in metalloregulation of the ars operon., J Biol Chem. 271(16):9291-7

 [2] 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

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

 [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



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