MERA_BACCE
ID MERA_BACCE Reviewed; 631 AA.
AC P16171;
DT 01-APR-1990, integrated into UniProtKB/Swiss-Prot.
DT 01-APR-1990, sequence version 1.
DT 03-AUG-2022, entry version 134.
DE RecName: Full=Mercuric reductase;
DE EC=1.16.1.1;
DE AltName: Full=Hg(II) reductase;
GN Name=merA;
OS Bacillus cereus.
OC Bacteria; Firmicutes; Bacilli; Bacillales; Bacillaceae; Bacillus;
OC Bacillus cereus group.
OX NCBI_TaxID=1396;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=RC607; TRANSPOSON=Tn5084;
RX PubMed=2536669; DOI=10.1128/jb.171.1.83-92.1989;
RA Wang Y., Moore M., Levinson H.S., Silver S., Walsh C.T., Mahler I.;
RT "Nucleotide sequence of a chromosomal mercury resistance determinant from a
RT Bacillus sp. with broad-spectrum mercury resistance.";
RL J. Bacteriol. 171:83-92(1989).
RN [2]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=RC607; TRANSPOSON=Tn5084;
RX PubMed=10559175; DOI=10.1128/jb.181.22.7080-7086.1999;
RA Gupta A., Phung L.T., Chakravarty L., Silver S.;
RT "Mercury resistance in Bacillus cereus RC607: transcriptional organization
RT and two new open reading frames.";
RL J. Bacteriol. 181:7080-7086(1999).
RN [3]
RP MUTAGENESIS OF TYR-264 AND TYR-605.
RX PubMed=7988676; DOI=10.1016/0014-5793(94)01180-x;
RA Rennex D., Pickett M., Bradley M.;
RT "In vivo and in vitro effects of mutagenesis of active site tyrosine
RT residues of mercuric reductase.";
RL FEBS Lett. 355:220-222(1994).
RN [4]
RP X-RAY CRYSTALLOGRAPHY (3.0 ANGSTROMS).
RC STRAIN=RC607;
RX PubMed=2067577; DOI=10.1038/352168a0;
RA Schiering N., Kabsch W., Moore M.J., Distefano M.D., Walsh C.T., Pai E.F.;
RT "Structure of the detoxification catalyst mercuric ion reductase from
RT Bacillus sp. strain RC607.";
RL Nature 352:168-172(1991).
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;
CC Note=Binds 1 FAD per subunit.;
CC -!- SUBUNIT: Homodimer.
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; AF138877; AAA83977.1; -; Genomic_DNA.
DR EMBL; AB066362; BAB62433.1; -; Genomic_DNA.
DR PIR; E32227; E32227.
DR AlphaFoldDB; P16171; -.
DR SMR; P16171; -.
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; 2.
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; 2.
DR SUPFAM; SSF55424; SSF55424; 1.
DR TIGRFAMs; TIGR02053; MerA; 1.
DR PROSITE; PS01047; HMA_1; 2.
DR PROSITE; PS50846; HMA_2; 2.
DR PROSITE; PS00076; PYRIDINE_REDOX_1; 1.
PE 1: Evidence at protein level;
KW Disulfide bond; FAD; Flavoprotein; Mercuric resistance; Mercury;
KW Metal-binding; NADP; Oxidoreductase; Redox-active center; Repeat;
KW Transposable element.
FT CHAIN 1..631
FT /note="Mercuric reductase"
FT /id="PRO_0000067995"
FT DOMAIN 2..66
FT /note="HMA 1"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00280"
FT DOMAIN 81..145
FT /note="HMA 2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00280"
FT BINDING 13
FT /ligand="a metal cation"
FT /ligand_id="ChEBI:CHEBI:25213"
FT /ligand_label="1"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00280"
FT BINDING 16
FT /ligand="a metal cation"
FT /ligand_id="ChEBI:CHEBI:25213"
FT /ligand_label="1"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00280"
FT BINDING 92
FT /ligand="a metal cation"
FT /ligand_id="ChEBI:CHEBI:25213"
FT /ligand_label="2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00280"
FT BINDING 95
FT /ligand="a metal cation"
FT /ligand_id="ChEBI:CHEBI:25213"
FT /ligand_label="2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00280"
FT BINDING 199..207
FT /ligand="FAD"
FT /ligand_id="ChEBI:CHEBI:57692"
FT /evidence="ECO:0000250"
FT BINDING 628
FT /ligand="Hg(2+)"
FT /ligand_id="ChEBI:CHEBI:16793"
FT BINDING 629
FT /ligand="Hg(2+)"
FT /ligand_id="ChEBI:CHEBI:16793"
FT DISULFID 207..212
FT /note="Redox-active"
FT /evidence="ECO:0000250"
FT MUTAGEN 264
FT /note="Y->F: 30-fold decrease in activity. 300-fold
FT decrease in activity; when associated with F-605."
FT /evidence="ECO:0000269|PubMed:7988676"
FT MUTAGEN 605
FT /note="Y->F: 10-fold decrease in activity. 300-fold
FT decrease in activity; when associated with F-264."
FT /evidence="ECO:0000269|PubMed:7988676"
FT MUTAGEN 605
FT /note="Y->H: 2-fold decrease in activity."
FT /evidence="ECO:0000269|PubMed:7988676"
SQ SEQUENCE 631 AA; 68072 MW; 0771662F8F1F4D00 CRC64;
MKKYRVNVQG MTCSGCEQHV AVALENMGAK AIEVDFRRGE AVFELPDDVK VEDAKNAIAD
ANYHPGEAEE FQSEQKTNLL KKYRLNVEGM TCTGCEEHIA VALENAGAKG IEVDFRRGEA
LFELPYDVDI DIAKTAITDA QYQPGEAEEI QVQSEKRTDV SLNDEGNYDY DYIIIGSGGA
AFSSAIEAVA LNAKVAMIER GTVGGTCVNV GCVPSKTLLR AGEINHLAKN NPFVGLHTSA
SNVDLAPLVK QKNDLVTEMR NEKYVNLIDD YGFELIKGES KFVNENTVEV NGNQITAKRF
LIATGASSTA PNIPGLDEVD YLTSTSLLEL KKVPNRLTVI GSGYIGMELG QLFHNLGSEV
TLIQRSERLL KEYDPEISEA ITKALTEQGI NLVTGATYER VEQDGDIKKV HVEINGKKRI
IEAEQLLIAT GRKPIQTSLN LHAAGVEVGS RGEIVIDDYL KTTNSRIYSA GDVTPGPQFV
YVAAYEGGLA ARNAIGGLNQ KVNLEVVPGV TFTSPSIATV GLTEQQAKEK GYEVKTSVLP
LDAVPRALVN RETTGVFKLV ADAKTLKVLG AHVVAENAGD VIYAATLAVK FGLTVGDLRE
TMAPYLTMAE GLKLAVLTFD KDVSKLSCCA G
