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Protein Domain : IPR001845

Name  HTH ArsR-type DNA-binding domain Short Name  HTH_ArsR_DNA-bd_dom
Type  Domain Description  The arsR-type HTH domain is a DNA-binding, winged helix-turn-helix (wHTH)domain present in transcription regulators of thearsR/smtB family, involved in stress-response to heavy metal ions. This familyof prokaryotic metal-sensing transcription repressors is named afterEscherichia coli arsR, an arsenic-responsive repressor of the ars operon forarsenate reductase and metal ion extrusion, and after Synechococcus PCC 7942smtB, a Zn(II)-responsive repressor of the smtA gene for a Zn sequesteringmetallothionein []. ArsR/smtB-like repressors of metal resistance operons specifically bind to the operator/promoter and seem to dissociate from the DNA in the presence of metal ions, permitting transcription of proteins involved in metal-ions efflux and/or detoxification.The crystal structure of the cyanobacterial smtB shows a fold of fivealpha-helices (H) and a pair of antiparallel beta-strands (B) in the topologyH1-H2-H3-H4-B1-B2-H5. Helices 3 and 4 comprise thehelix-turn-helix motif and the beta-sheet is called the wing as in other wHTH,such as the dtxR-type or the merR-type.Helix 4 is termed the recognition helix, like in other HTHs where it binds theDNA major groove. Most arsR/smtB-like metalloregulators form homodimers [].The dimer interface is formed by helix 5 and an N-terminal part []. Twodistinct metal-binding sites have been identified. The first site comprisescysteine thiolates located in the HTH in helix 3 and for some cases in theN terminus, called the alpha3(N) site [, , ]. The second metal-binding siteis located in helix 5 (and C terminus) and is called the alpha5(C) site. Thealpha3N site binds large thiophilic, toxic metals including Cd, Pb, and Bi, asin S. aureus cadC. ArsR lacks the N-terminal arm and its alpha3 sitecoordinates smaller thiophilic ions like As and Sb. The alpha5 site containscarboxylate and imidazole ligands and interacts preferentially withbiologically required metal ions including Zn, Co, and Ni. ArsR-typemetalloregulators contain one of these sites, both, or other potentialmetal-binding sites [, ]. Binding of metal ions to these sites leads toallosteric changes that can derepress the operator/promoter DNA. Themetal-inducible operons contain one or two imperfect 12-2-12 inverted repeats,which can be recognised by multimeric arsR-type metalloregulators.Some proteins known to contain an arsR-type HTH domain:Escherichia coli arsR, an arsenic-responsive transcription repressor of the arsenic resistance operon (ars) which encodes an arsenate reductase andmetal exporters.Synechococcus PCC 7942 smtB, a Zn(II)-responsive transcription repressor ofthe smtA gene that codes for a metallothionein. SmtB senses Co(II) and Cd(II) too, but Zn(II) is the preferred effector.Staphylococcus aureus cadC, a transcription regulator of the cadmiumresistance (cad) operon which encodes a Cd/Pb-specific efflux ATPase [].Mycobacterium tuberculosis cmtR, a Pb(II)/Cd(II)-sensing repressor [].

Publication Counts Displayer

0 Child Features

1 Contains

DB identifier Name Short Name Type
IPR018334 ArsR-type transcription regulator, HTH motif ArsR_HTH Conserved_site

4 Cross References

Identifier
Source . Name

Subject . Primary Identifier
PF01022 PFAM IPR001845
PR00778 PRINTS IPR001845
PS50987 PROFILE IPR001845
SM00418 SMART IPR001845

3 Data Sets

Name URL
TrEMBL data set http://www.ebi.ac.uk/trembl/
InterPro data set  
InterPro GO Annotation data set  

3 Found In

DB identifier Name Short Name Type
IPR016943 Uncharacterised conserved protein UCP030050, HTH transcriptional regulator, BH1869 UCP030050_HTH Family
IPR014075 SUF system FeS cluster assembly, SufR regulator, cyanobacteria SUF_FeS_clus_asmb_SufR_cyano Family
IPR016723 Transcription regulator, ArsR, predicted Tscrpt_reg_ArsR_prd Family

2 GO Annotation


Subject . Secondary Identifier

Subject . Name

Subject . Symbol

Ontology Term . Identifier

Ontology Term . Name
HTH ArsR-type DNA-binding domain   GO:0003700 sequence-specific DNA binding transcription factor activity
HTH ArsR-type DNA-binding domain   GO:0006355 regulation of transcription, DNA-templated

2 Ontology Annotations


Subject . Secondary Identifier

Subject . Name

Subject . Symbol

Ontology Term . Identifier

Ontology Term . Name
HTH ArsR-type DNA-binding domain   GO:0003700 sequence-specific DNA binding transcription factor activity
HTH ArsR-type DNA-binding domain   GO:0006355 regulation of transcription, DNA-templated

1 Parent Features

DB identifier Name Short Name Type
IPR011991 Winged helix-turn-helix DNA-binding domain WHTH_DNA-bd_dom Domain

1 Proteins

DB identifier Primary Accession
Organism . Name
E3NWW1_CAERE E3NWW1 Caenorhabditis remanei