ID   SMTB_SYNE7              Reviewed;         122 AA.
AC   P30340; Q31NP8;
DT   01-APR-1993, integrated into UniProtKB/Swiss-Prot.
DT   01-APR-1993, sequence version 1.
DT   27-MAR-2024, entry version 148.
DE   RecName: Full=Transcriptional repressor SmtB;
GN   Name=smtB; OrderedLocusNames=Synpcc7942_1291;
OS   Synechococcus elongatus (strain ATCC 33912 / PCC 7942 / FACHB-805)
OS   (Anacystis nidulans R2).
OC   Bacteria; Cyanobacteriota; Cyanophyceae; Synechococcales; Synechococcaceae;
OC   Synechococcus.
OX   NCBI_TaxID=1140;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8451191; DOI=10.1093/nar/21.4.921;
RA   Morby A.P., Turner J.S., Huckle J.W., Robinson N.J.;
RT   "SmtB is a metal-dependent repressor of the cyanobacterial metallothionein
RT   gene smtA: identification of a Zn inhibited DNA-protein complex.";
RL   Nucleic Acids Res. 21:921-925(1993).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8446025; DOI=10.1111/j.1365-2958.1993.tb01109.x;
RA   Huckle J.W., Morby A.P., Turner J.S., Robinson N.J.;
RT   "Isolation of a prokaryotic metallothionein locus and analysis of
RT   transcriptional control by trace metal ions.";
RL   Mol. Microbiol. 7:177-187(1993).
RN   [3]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RG   US DOE Joint Genome Institute;
RA   Copeland A., Lucas S., Lapidus A., Barry K., Detter J.C., Glavina T.,
RA   Hammon N., Israni S., Pitluck S., Schmutz J., Larimer F., Land M.,
RA   Kyrpides N., Lykidis A., Golden S., Richardson P.;
RT   "Complete sequence of chromosome 1 of Synechococcus elongatus PCC 7942.";
RL   Submitted (AUG-2005) to the EMBL/GenBank/DDBJ databases.
RN   [4]
RP   FUNCTION, AND MUTAGENESIS OF CYS-14; CYS-61; 105-HIS-HIS-106 AND CYS-121.
RX   PubMed=8871549; DOI=10.1093/nar/24.19.3714;
RA   Turner J.S., Glands P.D., Samson A.C., Robinson N.J.;
RT   "Zn2+-sensing by the cyanobacterial metallothionein repressor SmtB:
RT   different motifs mediate metal-induced protein-DNA dissociation.";
RL   Nucleic Acids Res. 24:3714-3721(1996).
RN   [5]
RP   SUBUNIT.
RX   PubMed=9398263; DOI=10.1021/bi971690v;
RA   Kar S.R., Adams A.C., Lebowitz J., Taylor K.B., Hall L.M.;
RT   "The cyanobacterial repressor SmtB is predominantly a dimer and binds two
RT   Zn2+ ions per subunit.";
RL   Biochemistry 36:15343-15348(1997).
RN   [6]
RP   FUNCTION, AND MUTAGENESIS OF CYS-14; CYS-61 AND HIS-106.
RX   PubMed=12146943; DOI=10.1021/bi020178t;
RA   VanZile M.L., Chen X., Giedroc D.P.;
RT   "Allosteric negative regulation of smt O/P binding of the zinc sensor,
RT   SmtB, by metal ions: a coupled equilibrium analysis.";
RL   Biochemistry 41:9776-9786(2002).
RN   [7]
RP   FUNCTION.
RX   PubMed=12407207; DOI=10.1093/pcp/pcf140;
RA   Morita E.H., Wakamatsu M., Uegaki K., Yumoto N., Kyogoku Y., Hayashi H.;
RT   "Zinc ions inhibit the protein-DNA complex formation between cyanobacterial
RT   transcription factor SmtB and its recognition DNA sequences.";
RL   Plant Cell Physiol. 43:1254-1258(2002).
RN   [8]
RP   X-RAY CRYSTALLOGRAPHY (2.2 ANGSTROMS).
RX   PubMed=9466913; DOI=10.1006/jmbi.1997.1443;
RA   Cook W.J., Kar S.R., Taylor K.B., Hall L.M.;
RT   "Crystal structure of the cyanobacterial metallothionein repressor SmtB: a
RT   model for metalloregulatory proteins.";
RL   J. Mol. Biol. 275:337-346(1998).
RN   [9]
RP   X-RAY CRYSTALLOGRAPHY (1.7 ANGSTROMS) IN COMPLEX WITH ZINC IONS, SUBUNIT,
RP   AND MUTAGENESIS OF CYS-14; CYS-61 AND CYS-121.
RX   PubMed=14568530; DOI=10.1016/j.jmb.2003.09.007;
RA   Eicken C., Pennella M.A., Chen X., Koshlap K.M., VanZile M.L.,
RA   Sacchettini J.C., Giedroc D.P.;
RT   "A metal-ligand-mediated intersubunit allosteric switch in related
RT   SmtB/ArsR zinc sensor proteins.";
RL   J. Mol. Biol. 333:683-695(2003).
CC   -!- FUNCTION: Transcriptional repressor of the expression of the smtA gene.
CC       Binds two zinc ions per dimer. The complex of DNA and SmtB is
CC       dissociated by zinc ions. {ECO:0000269|PubMed:12146943,
CC       ECO:0000269|PubMed:12407207, ECO:0000269|PubMed:8871549}.
CC   -!- SUBUNIT: Homodimer. {ECO:0000269|PubMed:14568530,
CC       ECO:0000269|PubMed:9398263}.
CC   -!- MISCELLANEOUS: The zinc ions are bound between subunits, so that
CC       residues from both subunits contribute to metal binding.
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DR   EMBL; X64585; CAA45872.1; -; Genomic_DNA.
DR   EMBL; CP000100; ABB57321.1; -; Genomic_DNA.
DR   PIR; S31197; S31197.
DR   RefSeq; WP_011242576.1; NZ_JACJTX010000003.1.
DR   PDB; 1R1T; X-ray; 1.70 A; A/B=1-122.
DR   PDB; 1R22; X-ray; 2.30 A; A/B=1-120.
DR   PDB; 1R23; X-ray; 2.00 A; A/B=1-122.
DR   PDB; 1SMT; X-ray; 2.20 A; A/B=1-122.
DR   PDBsum; 1R1T; -.
DR   PDBsum; 1R22; -.
DR   PDBsum; 1R23; -.
DR   PDBsum; 1SMT; -.
DR   AlphaFoldDB; P30340; -.
DR   BMRB; P30340; -.
DR   SMR; P30340; -.
DR   STRING; 1140.Synpcc7942_1291; -.
DR   PaxDb; 1140-Synpcc7942_1291; -.
DR   GeneID; 76400032; -.
DR   KEGG; syf:Synpcc7942_1291; -.
DR   eggNOG; COG0640; Bacteria.
DR   HOGENOM; CLU_097806_7_3_3; -.
DR   OrthoDB; 9794330at2; -.
DR   BioCyc; SYNEL:SYNPCC7942_1291-MONOMER; -.
DR   EvolutionaryTrace; P30340; -.
DR   Proteomes; UP000889800; Chromosome.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0003700; F:DNA-binding transcription factor activity; IEA:InterPro.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   CDD; cd00090; HTH_ARSR; 1.
DR   Gene3D; 1.10.10.10; Winged helix-like DNA-binding domain superfamily/Winged helix DNA-binding domain; 1.
DR   InterPro; IPR011991; ArsR-like_HTH.
DR   InterPro; IPR018334; ArsR_HTH.
DR   InterPro; IPR001845; HTH_ArsR_DNA-bd_dom.
DR   InterPro; IPR036388; WH-like_DNA-bd_sf.
DR   InterPro; IPR036390; WH_DNA-bd_sf.
DR   NCBIfam; NF033788; HTH_metalloreg; 1.
DR   PANTHER; PTHR43132; ARSENICAL RESISTANCE OPERON REPRESSOR ARSR-RELATED; 1.
DR   PANTHER; PTHR43132:SF6; TRANSCRIPTIONAL REPRESSOR SMTB HOMOLOG; 1.
DR   Pfam; PF01022; HTH_5; 1.
DR   PRINTS; PR00778; HTHARSR.
DR   SMART; SM00418; HTH_ARSR; 1.
DR   SUPFAM; SSF46785; Winged helix' DNA-binding domain; 1.
DR   PROSITE; PS00846; HTH_ARSR_1; 1.
DR   PROSITE; PS50987; HTH_ARSR_2; 1.
PE   1: Evidence at protein level;
KW   3D-structure; DNA-binding; Metal-binding; Reference proteome; Repressor;
KW   Transcription; Transcription regulation; Zinc.
FT   CHAIN           1..122
FT                   /note="Transcriptional repressor SmtB"
FT                   /id="PRO_0000160626"
FT   DOMAIN          28..122
FT                   /note="HTH arsR-type"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00340"
FT   DNA_BIND        62..81
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00340"
FT   BINDING         104
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="1"
FT   BINDING         106
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="1"
FT   BINDING         117
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="2"
FT   BINDING         120
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="2"
FT   MUTAGEN         14
FT                   /note="C->S: Does not abolish zinc binding or metal-induced
FT                   derepression."
FT                   /evidence="ECO:0000269|PubMed:12146943,
FT                   ECO:0000269|PubMed:14568530, ECO:0000269|PubMed:8871549"
FT   MUTAGEN         61
FT                   /note="C->S: Does not abolish zinc binding or metal-induced
FT                   derepression."
FT                   /evidence="ECO:0000269|PubMed:12146943,
FT                   ECO:0000269|PubMed:14568530, ECO:0000269|PubMed:8871549"
FT   MUTAGEN         105..106
FT                   /note="HH->RR: Loss of metal-induced derepression."
FT                   /evidence="ECO:0000269|PubMed:8871549"
FT   MUTAGEN         106
FT                   /note="H->Q: Loss of metal-induced derepression."
FT                   /evidence="ECO:0000269|PubMed:12146943"
FT   MUTAGEN         121
FT                   /note="C->S: Does not abolish zinc binding or metal-induced
FT                   derepression."
FT                   /evidence="ECO:0000269|PubMed:14568530,
FT                   ECO:0000269|PubMed:8871549"
FT   HELIX           22..24
FT                   /evidence="ECO:0007829|PDB:1R23"
FT   HELIX           30..43
FT                   /evidence="ECO:0007829|PDB:1R1T"
FT   HELIX           46..55
FT                   /evidence="ECO:0007829|PDB:1R1T"
FT   HELIX           62..69
FT                   /evidence="ECO:0007829|PDB:1R1T"
FT   HELIX           73..85
FT                   /evidence="ECO:0007829|PDB:1R1T"
FT   STRAND          88..94
FT                   /evidence="ECO:0007829|PDB:1R1T"
FT   STRAND          97..104
FT                   /evidence="ECO:0007829|PDB:1R1T"
FT   HELIX           105..117
FT                   /evidence="ECO:0007829|PDB:1R1T"
SQ   SEQUENCE   122 AA;  13544 MW;  A3C98CE13552B93F CRC64;
     MTKPVLQDGE TVVCQGTHAA IASELQAIAP EVAQSLAEFF AVLADPNRLR LLSLLARSEL
     CVGDLAQAIG VSESAVSHQL RSLRNLRLVS YRKQGRHVYY QLQDHHIVAL YQNALDHLQE
     CR
//