ID   MERA_ALCSP              Reviewed;         559 AA.
AC   P94188;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-1997, sequence version 1.
DT   03-AUG-2022, entry version 111.
DE   RecName: Full=Mercuric reductase;
DE            EC=1.16.1.1;
DE   AltName: Full=Hg(II) reductase;
GN   Name=merA;
OS   Alcaligenes sp.
OG   Plasmid IncHI2 pMER610.
OC   Bacteria; Proteobacteria; Betaproteobacteria; Burkholderiales;
OC   Alcaligenaceae; Alcaligenes.
OX   NCBI_TaxID=512;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RA   Nikiforov V., Yurieva O., Kholodii G., Minakhin L., Gorlenko Z.,
RA   Kalyaeva E., Mindlin S.;
RL   Submitted (DEC-1996) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Resistance to Hg(2+) in bacteria appears to be governed by a
CC       specialized system which includes mercuric reductase. MerA protein is
CC       responsible for volatilizing mercury as Hg(0).
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=H(+) + Hg + NADP(+) = Hg(2+) + NADPH; Xref=Rhea:RHEA:23856,
CC         ChEBI:CHEBI:15378, ChEBI:CHEBI:16170, ChEBI:CHEBI:16793,
CC         ChEBI:CHEBI:57783, ChEBI:CHEBI:58349; EC=1.16.1.1;
CC   -!- COFACTOR:
CC       Name=FAD; Xref=ChEBI:CHEBI:57692; Evidence={ECO:0000250};
CC       Note=Binds 1 FAD per subunit. {ECO:0000250};
CC   -!- SUBUNIT: Homodimer. {ECO:0000250}.
CC   -!- MISCELLANEOUS: The active site is a redox-active disulfide bond.
CC   -!- SIMILARITY: Belongs to the class-I pyridine nucleotide-disulfide
CC       oxidoreductase family. {ECO:0000305}.
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DR   EMBL; Y08993; CAA70190.1; -; Genomic_DNA.
DR   AlphaFoldDB; P94188; -.
DR   SMR; P94188; -.
DR   GO; GO:0050660; F:flavin adenine dinucleotide binding; IEA:InterPro.
DR   GO; GO:0016152; F:mercury (II) reductase activity; IEA:UniProtKB-EC.
DR   GO; GO:0045340; F:mercury ion binding; IEA:InterPro.
DR   GO; GO:0050661; F:NADP binding; IEA:InterPro.
DR   GO; GO:0016668; F:oxidoreductase activity, acting on a sulfur group of donors, NAD(P) as acceptor; IEA:InterPro.
DR   GO; GO:0045454; P:cell redox homeostasis; IEA:InterPro.
DR   GO; GO:0050787; P:detoxification of mercury ion; IEA:InterPro.
DR   CDD; cd00371; HMA; 1.
DR   Gene3D; 3.30.390.30; -; 1.
DR   Gene3D; 3.50.50.60; -; 2.
DR   InterPro; IPR036188; FAD/NAD-bd_sf.
DR   InterPro; IPR023753; FAD/NAD-binding_dom.
DR   InterPro; IPR016156; FAD/NAD-linked_Rdtase_dimer_sf.
DR   InterPro; IPR017969; Heavy-metal-associated_CS.
DR   InterPro; IPR006121; HMA_dom.
DR   InterPro; IPR036163; HMA_dom_sf.
DR   InterPro; IPR021179; Mercury_reductase_MerA.
DR   InterPro; IPR001100; Pyr_nuc-diS_OxRdtase.
DR   InterPro; IPR004099; Pyr_nucl-diS_OxRdtase_dimer.
DR   InterPro; IPR012999; Pyr_OxRdtase_I_AS.
DR   Pfam; PF00403; HMA; 1.
DR   Pfam; PF07992; Pyr_redox_2; 1.
DR   Pfam; PF02852; Pyr_redox_dim; 1.
DR   PIRSF; PIRSF000350; Mercury_reductase_MerA; 1.
DR   SUPFAM; SSF51905; SSF51905; 1.
DR   SUPFAM; SSF55008; SSF55008; 1.
DR   SUPFAM; SSF55424; SSF55424; 1.
DR   TIGRFAMs; TIGR02053; MerA; 1.
DR   PROSITE; PS01047; HMA_1; 1.
DR   PROSITE; PS50846; HMA_2; 1.
DR   PROSITE; PS00076; PYRIDINE_REDOX_1; 1.
PE   3: Inferred from homology;
KW   Disulfide bond; FAD; Flavoprotein; Mercuric resistance; Mercury;
KW   Metal-binding; NADP; Oxidoreductase; Plasmid; Redox-active center.
FT   CHAIN           1..559
FT                   /note="Mercuric reductase"
FT                   /id="PRO_0000067994"
FT   DOMAIN          1..64
FT                   /note="HMA"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00280"
FT   BINDING         10
FT                   /ligand="a metal cation"
FT                   /ligand_id="ChEBI:CHEBI:25213"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00280"
FT   BINDING         13
FT                   /ligand="a metal cation"
FT                   /ligand_id="ChEBI:CHEBI:25213"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00280"
FT   BINDING         126..134
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         556
FT                   /ligand="Hg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:16793"
FT   BINDING         557
FT                   /ligand="Hg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:16793"
FT   DISULFID        134..139
FT                   /note="Redox-active"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   559 AA;  58020 MW;  0603DDD6B13CB519 CRC64;
     MYLNITGMTC DSCATHVKDA LEKVPGVLSA LVSYPKGSAQ LATDPGTSPE ALTAAVAGLG
     YKATPADAPS TSARGRLLGK ALGWLGGGDK AGGDGDGLHV AVIGSGAAMA AALKAVEQGA
     NVTLIERGTI GGTCVNVGCV PSKIMIRAAH IAHLRRESPF DGGIAATVPA IDRSKLLAQQ
     QARVDELRHA KYEGILDDNP AITVLHGEAR FKDDQSLAVR LNDGGERVVA FDRCLVATGA
     SPAVPPIPGL KESPYWTSTE ALVSDTIPER LAVIGSSVVA LELAQAFARL GSKVTILARS
     TLFFREDPAI GEAVTAAFRA EGIKVLEYTQ ASQVAHVDGE FVLTTGYGEI RADQLLVATG
     RAPNTRSLAL EAAGVAANAQ GAIVIDKGMR TSTPHIYAAG DCTDQPQFVY VAAAAGTRAA
     INMTGGDAAL DLTAMPAVVF TDPQVATVGY SEAEAHHDGI ETDSRTLTLD NVPRALANFD
     TRGFIKLVIE EGSGRLIGVQ AVAPEAGELI QTAVLAIRNR MTVQELADQL FPYLTMVEGL
     KLAAQTFSKD VKQLSCCAG