Information on EC 1.16.1.1 - mercury(II) reductase

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The enzyme appears in viruses and cellular organisms

EC NUMBER
COMMENTARY
1.16.1.1
-
RECOMMENDED NAME
GeneOntology No.
mercury(II) reductase
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
Hg + NADP+ + H+ = Hg2+ + NADPH
show the reaction diagram
-
-
-
-
Hg + NADP+ + H+ = Hg2+ + NADPH
show the reaction diagram
FAD mediates the transfer of electrons between NADPH and Hg2+ bound to an adjacent pair of cysteine thiols (C136 and C141) in the buried active site, while a second pair of cysteines (C558 and C559) on the C-terminal tail mediates transfer of Hg2+ from other protein and small molecule thiols in solution to the active site cysteines through a ligand exchange mechanism, structure-function study, overview
-
REACTION TYPE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
redox reaction
-
-
-
-
PATHWAY
KEGG Link
MetaCyc Link
phenylmercury acetate degradation
-
SYSTEMATIC NAME
IUBMB Comments
Hg:NADP+ oxidoreductase
A dithiol enzyme.
SYNONYMS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
Mer A
-
-
-
-
MerA
-
-
MerA
Q9WTI5
-
MerA
E0XF09
-
MerA protein
-
-
mercurate(II) reductase
-
-
-
-
mercuric ion reductase
-
-
-
-
mercuric ion reductase
-
-
mercuric ion reductase
E0XF09
-
mercuric reductase
-
-
-
-
mercuric reductase
-
-
mercuric reductase
-
-
mercuric reductase
-
-
-
mercuric reductase
-
-
mercuric reductase
Q9WTI5
-
mercuric reductase
-
-
mercuric reductase
Pseudomonas aeruginosa PAO 9501
-
;
-
mercuric reductase
Pseudomonas aeruginosa PAO9501, Pseudomonas aeruginosa PAO9501 (pVS1)
-
-
-
mercury reductase
-
-
-
-
reduced NADP:mercuric ion oxidoreductase
-
-
-
-
reductase, mercurate(II)
-
-
-
-
Tn501 mercuric ion reductase
-
-
CAS REGISTRY NUMBER
COMMENTARY
67880-93-7
-
ORGANISM
COMMENTARY
LITERATURE
SEQUENCE CODE
SEQUENCE DB
SOURCE
Acidithiobacillus ferrooxidans TFI 29
TFI 29
-
-
Manually annotated by BRENDA team
isolated from surface and sub-surface floodplain soil, Oak Ridge, USA, gene merA
-
-
Manually annotated by BRENDA team
Alcanivorax sp.
strain EPR 10 resistant to up to 0.075 mM Hg2+; strain EPR5 resistant to up to 0.01 mM Hg2+
-
-
Manually annotated by BRENDA team
Alcanivorax sp.
strain EPR6 resistant to up to 0.075 mM Hg2+
Q5ILH5
SwissProt
Manually annotated by BRENDA team
Alcanivorax sp.
strain EPR7, resistant to up to 0.075 mM Hg2+
SwissProt
Manually annotated by BRENDA team
Alcanivorax sp.
strain EPR8, resistant to up to 0.075 mM Hg2+
SwissProt
Manually annotated by BRENDA team
Alcanivorax sp. EPR
strain EPR 10 resistant to up to 0.075 mM Hg2+
-
-
Manually annotated by BRENDA team
Alcanivorax sp. EPR5
strain EPR5 resistant to up to 0.01 mM Hg2+
-
-
Manually annotated by BRENDA team
Alcanivorax sp. EPR6
strain EPR6 resistant to up to 0.075 mM Hg2+
Q5ILH5
SwissProt
Manually annotated by BRENDA team
strain EPR7, resistant to up to 0.075 mM Hg2+
SwissProt
Manually annotated by BRENDA team
Alcanivorax sp. EPR8
strain EPR8, resistant to up to 0.075 mM Hg2+
SwissProt
Manually annotated by BRENDA team
Azotobacter chroococcum SS2
SS2
-
-
Manually annotated by BRENDA team
Citrobacter sp.
-
-
-
Manually annotated by BRENDA team
containing the cloned mercury resistance genes from plasmid NR1
-
-
Manually annotated by BRENDA team
enzyme encoded by Tn5044 merA gene, thermosensitive resistance to mercury, expression and functional activity of enzyme are severely inhibited at 37-41.5C
-
-
Manually annotated by BRENDA team
Tn501 mercuric ion reductase
-
-
Manually annotated by BRENDA team
W3110 lacIq containing the plasmid pPSO1
-
-
Manually annotated by BRENDA team
Escherichia coli PWS1
PWS1
-
-
Manually annotated by BRENDA team
Flavobacterium rigense
strain PR2
-
-
Manually annotated by BRENDA team
Flavobacterium rigense PR2
strain PR2
-
-
Manually annotated by BRENDA team
Halomonas sp.
strain resistant to up to 0.04 mM Hg2+
-
-
Manually annotated by BRENDA team
strain resistant to up to 0.05 mM Hg2+
-
-
Manually annotated by BRENDA team
enzyme is encoded by the plasmid pVT1
-
-
Manually annotated by BRENDA team
Oerskovia sp.
-
-
-
Manually annotated by BRENDA team
MR-2 strain
-
-
Manually annotated by BRENDA team
Penicillium sp. MR-2
MR-2 strain
-
-
Manually annotated by BRENDA team
mercury-resistant Escherichia coli strain containing plasmid R100 encoding gene merA in the mer operon
-
-
Manually annotated by BRENDA team
plasmid R100; Escherichia coli containing plasmid R100 encoding gene merA
UniProt
Manually annotated by BRENDA team
strain resistant to up to 0.05 mM Hg2+
-
-
Manually annotated by BRENDA team
strain resistant to up to 0.05 mM Hg2+
UniProt
Manually annotated by BRENDA team
; PAO9501 (pVS1)
-
-
Manually annotated by BRENDA team
enzyme is encoded by the transposon Tn501
-
-
Manually annotated by BRENDA team
PAO9501; strain PAO 9501
-
-
Manually annotated by BRENDA team
possessing the Tn501 plasmid, a transposon determining resistance to mercuric ions
-
-
Manually annotated by BRENDA team
strain PAO 9501; Tn501-encoded
-
-
Manually annotated by BRENDA team
Pseudomonas aeruginosa PAO 9501
strain PAO 9501
-
-
Manually annotated by BRENDA team
Pseudomonas aeruginosa PAO9501
PAO9501
-
-
Manually annotated by BRENDA team
Pseudomonas aeruginosa PAO9501 (pVS1)
PAO9501 (pVS1)
-
-
Manually annotated by BRENDA team
KT2442::mer-73
-
-
Manually annotated by BRENDA team
Pseudomonas putida KT2442::mer-73
KT2442::mer-73
-
-
Manually annotated by BRENDA team
strain resistant to up to 0.075 mM Hg2+
-
-
Manually annotated by BRENDA team
expressed by Pseudomonas putida
-
-
Manually annotated by BRENDA team
plasmid-encoded mer operon
E0XF09
UniProt
Manually annotated by BRENDA team
Streptomyces coelicolor M130
strain M130
-
-
Manually annotated by BRENDA team
Streptomyces espinosus 5
strain 5
-
-
Manually annotated by BRENDA team
strain 1326; strain 8
-
-
Manually annotated by BRENDA team
Streptomyces lividans 8
strain 8
-
-
Manually annotated by BRENDA team
analysis of enzyme in several thermophylic crenarchaeal and gram-positive taxa isolates from a hot spring. An essential role for mercuric reductase is evident during growth in the mercury-contaminated environment. Despite environmental selection for mercury resistance and the proximity of community members, the enzyme retains the two distinct prokaryotic forms and avoids genetic homogenization
-
-
Manually annotated by BRENDA team
isolated from surface and sub-surface floodplain soil, Oak Ridge, USA, gene merA
-
-
Manually annotated by BRENDA team
isolated from surface and sub-surface floodplain soil, Oak Ridge, USA, gene merA
-
-
Manually annotated by BRENDA team
Yersinia enterolytica
138A14
-
-
Manually annotated by BRENDA team
Yersinia enterolytica 138A14
138A14
-
-
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
physiological function
E0XF09
organomercurials are converted to less toxic Hg(0) in the cytosol by the sequential action of organomercurial lyase MerB and mercuric ion reductase MerA, requiring transfer of Hg(II) from MerB to MerA, with transfer to the metallochaperone-like NmerA domain as the kinetically favored pathway in this coevolved system, overview. Hg(II) removal from MerB by the N-terminal domain, NmerA, and catalytic core C-terminal cysteine pairs of its coevolved MerA and by GSH, the major competing cellular thiol in gamma-proteobacteria. The reaction with a 10fold excess of NmerA over HgMerB removes about 92% of Hg(II), while similar extents of reaction require more than 1000fold excess of GSH. NmerA reacts more completely than GSH with HgMerB
physiological function
Q9WTI5
MerA catalyzes the bioconversion of toxic Hg2+ to the least toxic elemental Hg0
evolution
E0XF09
organomercurials are converted to less toxic Hg(0) in the cytosol by the sequential action of organomercurial lyase MerB and mercuric ion reductase MerA, requiring transfer of Hg(II) from MerB to MerA, with transfer to the metallochaperone-like NmerA domain as the kinetically favored pathway in this coevolved system, overview. Hg(II) removal from MerB by the N-terminal domain, NmerA, and catalytic core C-terminal cysteine pairs of its coevolved MerA and by GSH, the major competing cellular thiol in gamma-proteobacteria. The reaction with a 10fold excess of NmerA over HgMerB removes about 92% of Hg(II), while similar extents of reaction require more than 1000fold excess of GSH
additional information
-
MerA is an inducible NADPH-dependent and flavin containing disulfide oxidoreductase enzyme. MerA-encoding plasmid R100-containing Escherichia coli strains are involved in environmental inorganic mercury detoxification
additional information
-
comparison of structural changes upon metal binding in normally appended metal binding proteins: NmerA with and without Hg2+ , PDB entry 2KT3 and 2KT2, respectively
SUBSTRATE
PRODUCT                      
REACTION DIAGRAM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
2,4,6-trinitrobenzenesulfonate + NADPH
? + NADP+
show the reaction diagram
Pseudomonas aeruginosa, Pseudomonas aeruginosa PAO9501, Pseudomonas aeruginosa PAO 9501
-
-
-
?
Hg + NADP+ + H+
Hg2+ + NADPH
show the reaction diagram
-
-
-
-
?
Hg + NADP+ + H+
Hg2+ + NADPH
show the reaction diagram
E0XF09
-
-
-
?
Hg + NADP+ + H+
Hg2+ + NADPH
show the reaction diagram
Q9WTI5
-, MerA catalyzes the bioconversion of toxic Hg2+ to the least toxic elemental Hg0, and is capable of reducing the Hg2+, via NADPH as an electron donor
-
-
?
Hg + NADP+ + H+
Hg2+ + NADPH
show the reaction diagram
E0XF09
organomercurials are converted to less toxic Hg(0) in the cytosol by the sequential action of organomercurial lyase MerB and mercuric ion reductase MerA, requiring transfer of Hg(II) from MerB to MerA, with transfer to the metallochaperone-like NmerA domain as the kinetically favored pathway in this coevolved system, overview
-
-
?
Hg + NADP+ + H+
Hg2+ + NADPH
show the reaction diagram
-
Cys11 and Cys14 are involved in metal binding, role for Tyr62 in modulating the pKa values of the cysteine thiols
-
-
?
Hg2+ + azure A
Hg + ?
show the reaction diagram
Escherichia coli, Escherichia coli PWS1
-
-
-
-
?
Hg2+ + NADH
Hg + NAD+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADH
Hg + NAD+ + H+
show the reaction diagram
Flavobacterium rigense
-
-
-
-
?
Hg2+ + NADH
Hg + NAD+ + H+
show the reaction diagram
Yersinia enterolytica
-
-
-
-
?
Hg2+ + NADH
Hg + NAD+ + H+
show the reaction diagram
-
nearly identical activity with NADPH or NADH
-
-
?
Hg2+ + NADH
Hg + NAD+ + H+
show the reaction diagram
-
very little activity with NADH
-
?
Hg2+ + NADH
Hg + NAD+ + H+
show the reaction diagram
Flavobacterium rigense PR2
-
-
-
-
?
Hg2+ + NADH
Hg + NAD+ + H+
show the reaction diagram
Yersinia enterolytica 138A14
-
-
-
-
?
Hg2+ + NADH
Hg + NAD+ + H+
show the reaction diagram
Penicillium sp. MR-2
-
very little activity with NADH
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Citrobacter sp.
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Flavobacterium rigense
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Yersinia enterolytica
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Oerskovia sp.
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Q97VD9
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
nearly identical activity with NADPH or NADH
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
inducible enzyme
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Flavobacterium rigense
-
mercury resistance is due to the sequential action of two mercury-detoxificating enzymes, organomercurial lyase and mercuric reductase. Enzyme is induced by Hg2+ and organomercurials
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
last step in bacterial mercury detoxification pathway
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
the enzyme is a key component of an organomercurial detoxification system
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Q97VD9
the merA mutant exhibits mercury sensitivity relative to wild type and is defective in elemental mercury volatilization
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-, inducible enzyme
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Pseudomonas aeruginosa PAO9501 (pVS1)
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Flavobacterium rigense PR2
-
-, mercury resistance is due to the sequential action of two mercury-detoxificating enzymes, organomercurial lyase and mercuric reductase. Enzyme is induced by Hg2+ and organomercurials
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Streptomyces coelicolor M130
-
-, inducible enzyme
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Acidithiobacillus ferrooxidans TFI 29
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Yersinia enterolytica 138A14
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Streptomyces espinosus 5
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Escherichia coli PWS1
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Pseudomonas aeruginosa PAO9501
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Pseudomonas aeruginosa PAO9501
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Pseudomonas putida KT2442::mer-73
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Pseudomonas aeruginosa PAO 9501
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Azotobacter chroococcum SS2
-
-
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Penicillium sp. MR-2
-
-, the enzyme is a key component of an organomercurial detoxification system
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Streptomyces lividans 8
-
-, inducible enzyme
-
-
?
Hg2+ + NADPH
Hg(0) + NADP+
show the reaction diagram
-
key enzyme in detoxification of mercury in bacteria
-
-
r
Hg2+ + NADPH
Hg(0) + NADP+
show the reaction diagram
-
mercuric ion resistance in bacteria requires transport of Hg2+ ions into the cytoplasmic compartment where they are reduced to the less toxic metallic mercury Hg0 by mercuric reductase, interactions between the inner membrane mercuric ion transporter, MerT, and the N-terminal domain of cytoplasmic mercuric reductase, transport is the rate-limiting step in mercury detoxification, overview
-
-
r
Hg2+ + neutral red
Hg + ?
show the reaction diagram
Escherichia coli, Escherichia coli PWS1
-
-
-
-
?
NADPH + Hg2+
NADP+ + Hg
show the reaction diagram
-
-
-
-
?
NADPH + Hg2+
NADP+ + Hg
show the reaction diagram
Pseudomonas aeruginosa PAO9501 (pVS1)
-
-
-
-
?
NADPH + Hg2+
NADP+ + Hg
show the reaction diagram
Pseudomonas aeruginosa PAO9501
-
-
-
-
?
NADPH + Hg2+
NADP+ + Hg
show the reaction diagram
Pseudomonas aeruginosa PAO 9501
-
-
-
-
?
merthiolate + NADPH
? + NADP+
show the reaction diagram
Yersinia enterolytica, Yersinia enterolytica 138A14
-
-
-
-
?
additional information
?
-
-
Tyr264 and Tyr605 are involved in substrate binding, Tyr264 is important for catalysis, possibly by destabilizing the binding of Hg(II) to the two ligating thiolates at the active site
-
-
-
additional information
?
-
-
Cys558 plays a more important role in forming the reducible complex with Hg(II), while both Cys558 and Cys559 seem to be involved in efficient scavenging of Hg(II)
-
-
-
additional information
?
-
E0XF09
proposed model for reaction of NmerA with HgMerB and of GSH with HgMerB, overview
-
-
-
additional information
?
-
-
structure-function study of the N-terminal HMA domain NmerA of Tn501 mercuric ion reductase , i.e. MerA, using NMR and spectral techniques, overview. Determination of NMR solution structures of reduced and Hg2+-bound forms of NmerA
-
-
-
additional information
?
-
-
Tyr264 and Tyr605 are involved in substrate binding, Tyr264 is important for catalysis, possibly by destabilizing the binding of Hg(II) to the two ligating thiolates at the active site
-
-
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
Hg + NADP+ + H+
Hg2+ + NADPH
show the reaction diagram
-
-
-
-
?
Hg + NADP+ + H+
Hg2+ + NADPH
show the reaction diagram
Q9WTI5
MerA catalyzes the bioconversion of toxic Hg2+ to the least toxic elemental Hg0, and is capable of reducing the Hg2+, via NADPH as an electron donor
-
-
?
Hg + NADP+ + H+
Hg2+ + NADPH
show the reaction diagram
E0XF09
organomercurials are converted to less toxic Hg(0) in the cytosol by the sequential action of organomercurial lyase MerB and mercuric ion reductase MerA, requiring transfer of Hg(II) from MerB to MerA, with transfer to the metallochaperone-like NmerA domain as the kinetically favored pathway in this coevolved system, overview
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
inducible enzyme
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Flavobacterium rigense
-
mercury resistance is due to the sequential action of two mercury-detoxificating enzymes, organomercurial lyase and mercuric reductase. Enzyme is induced by Hg2+ and organomercurials
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
last step in bacterial mercury detoxification pathway
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
the enzyme is a key component of an organomercurial detoxification system
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Q97VD9
the merA mutant exhibits mercury sensitivity relative to wild type and is defective in elemental mercury volatilization
-
-
?
Hg2+ + NADPH
Hg(0) + NADP+
show the reaction diagram
-
key enzyme in detoxification of mercury in bacteria
-
-
r
Hg2+ + NADPH
Hg(0) + NADP+
show the reaction diagram
-
mercuric ion resistance in bacteria requires transport of Hg2+ ions into the cytoplasmic compartment where they are reduced to the less toxic metallic mercury Hg0 by mercuric reductase
-
-
r
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
-
inducible enzyme
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Flavobacterium rigense PR2
-
mercury resistance is due to the sequential action of two mercury-detoxificating enzymes, organomercurial lyase and mercuric reductase. Enzyme is induced by Hg2+ and organomercurials
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Streptomyces coelicolor M130
-
inducible enzyme
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Penicillium sp. MR-2
-
the enzyme is a key component of an organomercurial detoxification system
-
-
?
Hg2+ + NADPH
Hg + NADP+ + H+
show the reaction diagram
Streptomyces lividans 8
-
inducible enzyme
-
-
?
additional information
?
-
E0XF09
proposed model for reaction of NmerA with HgMerB and of GSH with HgMerB, overview
-
-
-
COFACTOR
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
FAD
-
activity is dependent upon
FAD
Yersinia enterolytica
-
contains FAD
FAD
-
mediates the transfer of electrons betweenNADPH and Hg2+
NADH
Flavobacterium rigense
-
-
NADH
-
very little activity
NADH
-
some activation
NADH
-
NADPH stimulates more effectively than NADH
NADH
-
strain 1326, NADPH stimulates more effectively than NADH
NADH
-
nearly identical activity with NADPH or NADH
NADH
Yersinia enterolytica
-
slowly oxidized
NADPH
Flavobacterium rigense
-
-
NADPH
-
; the first two steps of the reaction involve 1 mol NADPH per mol FAD, the third requires a second equivalent of NADPH
NADPH
-
; in presence of 1 mM cysteine only one equivalent of NADPH per FAD is required for full activation
NADPH
-
nearly identical activity with NADPH or NADH
NADPH
Yersinia enterolytica
-
optimal with a NADPH concentration near 0.05 mM
NADPH
-
in the presence of an excess of NADPH, the final product of the reaction is probably an NADPH complex of two-electron-reduced enzyme, but below pH 6 the final spectrum becomes less intense suggesting a partial formation of four-electron-reduced enzyme
NADPH
Yersinia enterolytica
-
-
NADPH
-
dependent on
NADPH
Q9WTI5
-
METALS and IONS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
INHIBITORS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
Ag+
Flavobacterium rigense
-
0.1 mM AgNO3, complete inhibition
Ag2+
Yersinia enterolytica
-
-
Bi3+
Flavobacterium rigense
-
0.1 mM Bi(NO3)3, 34% inhibition
Bi3+
-
0.1 mM, 40% inhibition
Cd2+
Yersinia enterolytica
-
weak inhibition
Cl-
-
inhibitory above 0.1 M, complete inhibition at 1 M
CoCl2
Flavobacterium rigense
-
0.1 mM CoCl2, 10% inhibition
Cu2+
Flavobacterium rigense
-
0.1 mM, 40% inhibition
Cu2+
Yersinia enterolytica
-
-
Cu2+
-
0.1 mM, 44% inhibition
Hg2+
-
pronounced substrate inhibition
HgCl2
Yersinia enterolytica
-
activity is inhibited by an excess of HgCl2
HgCl2
-
activity is inhibited by an excess of HgCl2
KCN
Flavobacterium rigense
-
0.1 mM, 20% inhibition
NADPH
-
substrate inhibition of the reaction with 2,4,6-trinitrobenzenesulfonate and NADPH
NaN3
Flavobacterium rigense
-
0.1 mM, 50% inhibition
NEM
Flavobacterium rigense
-
0.1 mM, 50% inhibition
NEM
-
2 mM, 60% inhibition
Ni2+
Yersinia enterolytica
-
-
Ni2+
-
0.1 mM, 62% inhibition
Pb(NO3)2
Flavobacterium rigense
-
0.1 mM, 78% inhibition
Pb2+
-
0.1 mM, 60% inhibition
Zn2+
Flavobacterium rigense
-
0.1 mM, 40% inhibition
Zn2+
-
0.1 mM, 60% inhibition
Mn2+
Yersinia enterolytica
-
weak inhibition
additional information
-
no effective product inhibition by NADP+
-
additional information
-
no inhibition by 2,4,6-trinitrobenzenesulfonate; not inhibitory: 0.1 mM NADP+; not inhibitory: 100 microM 2,4,6-trinitrobenzenesulfonate
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
2-mercaptoethanol
-
activates, optimal concentration is 3.3 mM
2-mercaptoethanol
-
thiol compound required, optimal concentration is 0.5 mM
2-mercaptoethanol
Yersinia enterolytica
-
increases activity
2-mercaptoethanol
Yersinia enterolytica
-
required for activity with merthiolate
2-mercaptoethanol
-
optimal concentration: 2 mM; required
cysteine
-
thiol compound required
cysteine
-
1 mM, 30 min preincubation, relative initial rate 121%; 30 mM, 30 min preincubation, relative initial rate 200%
dithiothreitol
-
thiol compound required
EDTA
-
required for maximal activity
NADP+
-
100 microM, 30 min preincubation, relative initial rate 108%
NADP+
-
strong stimulation of the reaction with 2,4,6-trinitrobenzenesulfonate and NADPH
NADPH
-
100 microM, 30 min preincubation, relative initial rate 151%, 10 min preincubation with NADPH results in an increase of reactive thiol groups
thioglycolate
-
thiol compound required
thiol
-
exogenous thiols are required for catalytic reduction of Hg(II) to Hg2+, due to prevention or reversal of formation of an abortive complex of Hg(II) with the thiol/thiolate pair of two-electron reduced enzyme
EDTA
-
1 mM, 30 min preincubation, relative initial rate 104%; no effect
additional information
-
0.1 mM NADP+ stimulates the 2,4,6-trinitrobenzenesulfonate-dependent NADPH oxidation more than 10fold
-
KM VALUE [mM]
KM VALUE [mM] Maximum
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.0019
-
Hg2+
-
mutant enzyme Y605F
0.0032
-
Hg2+
-
1 mM cysteine, 25C, pH 7.3; in presence of 1 mM cysteine
0.005
-
Hg2+
-
wild-type enzyme, aerobic conditions
0.0057
-
Hg2+
-
wild-type enzyme, anaerobic conditions
0.014
-
Hg2+
-
pH 7.2, 30C, detailed kinetics
0.021
-
Hg2+
-
mutant enzyme C559A, anaerobic conditions
0.025
-
Hg2+
-
mutant enzyme C559A, aerobic conditions
0.03
-
Hg2+
-
-
0.035
-
Hg2+
-
recombinant catalytic core, presence of N-terminal sequence NmerA, 25C, pH 7.3
0.045
-
Hg2+
-
mutant enzyme C558A, aerobic conditions
0.052
-
Hg2+
-
mutant enzyme C558A, anaerobic conditions
0.297
-
Hg2+
-
full-length enzyme, 25C, pH 7.3
1.177
-
Hg2+
-
recombinant catalytic core, 25C, pH 7.3
0.0088
-
HgCl2
-
-
0.0004
-
NADPH
-
25C, pH 7.3; in presence of 1 mM cysteine
0.2
-
HgCl2
Yersinia enterolytica
-
20 mM 2-mercaptoethanol
additional information
-
additional information
-
-
-
additional information
-
additional information
-
-
-
additional information
-
additional information
Yersinia enterolytica
-
the Km-value for HgCl2 is dependent on the concentration of exogenous thiol compounds
-
additional information
-
additional information
E0XF09
steady-state kinetic analysis, overview, apparent second-order rate constant for Hg(II) transfer from MerB to NmerA
-
TURNOVER NUMBER [1/s]
TURNOVER NUMBER MAXIMUM[1/s]
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.383
-
Hg2+
-
mutant enzyme C558A, anaerobic conditions
0.5
-
Hg2+
-
mutant enzyme Y605F
0.5
-
Hg2+
-
mutant enzyme C558A, aerobic conditions
0.7
-
Hg2+
-
6C, pH 7.3
4.85
-
Hg2+
-
mutant enzyme C559A, anaerobic conditions
7
-
Hg2+
-
recombinant catalytic core, 25C, pH 7.3
7.43
-
Hg2+
-
wild-type enzyme, aerobic conditions
7.63
-
Hg2+
-
mutant enzyme C559A, aerobic conditions
9
-
Hg2+
-
full-length enzyme, 25C, pH 7.3
12
-
Hg2+
-
-
12
-
Hg2+
-
recombinant catalytic core, presence of N-terminal sequence NmerA, 25C, pH 7.3
13.5
-
Hg2+
-
wild-type enzyme, aerobic conditions
additional information
-
additional information
-
-
-
Ki VALUE [mM]
Ki VALUE [mM] Maximum
INHIBITOR
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.016
-
Ag2+
Yersinia enterolytica
-
-
0.018
-
Cu2+
Yersinia enterolytica
-
-
0.0175
-
Ni2+
Yersinia enterolytica
-
-
SPECIFIC ACTIVITY [µmol/min/mg]
SPECIFIC ACTIVITY MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
2.08
-
Yersinia enterolytica
-
-
6.8
-
Flavobacterium rigense
-
-
additional information
-
-
-
pH OPTIMUM
pH MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
7
-
-
soluble and immobilized mercuric reductase
7.3
-
Yersinia enterolytica
-
-
7.3
-
E0XF09
assay at
pH RANGE
pH RANGE MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
6.5
9
-
pH 6.5: about 60% of maximal activity, pH 9.0: about 50% of maximal activity
TEMPERATURE OPTIMUM
TEMPERATURE OPTIMUM MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
25
-
E0XF09
assay at
37
43
Yersinia enterolytica
-
-
45
-
Alcanivorax sp.
-, Q5ILH3, Q5ILH4, Q5ILH5
-
45
-
Halomonas sp., Marinobacter sp.
-
-
45
-
-, Q5ILH6
;
pI VALUE
pI VALUE MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
5
-
-
isoelectric focusing
5.1
-
-
isoelectric focusing
SOURCE TISSUE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
SOURCE
Streptomyces espinosus 5, Streptomyces lividans 1326, Streptomyces lividans 8
-
-
-
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
MOLECULAR WEIGHT
MOLECULAR WEIGHT MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
58000
-
-
gel filtration
110000
-
-
gel filtration
123000
-
-
gel filtration
130000
-
-
gel filtration
142000
-
-
gel filtration
190000
-
-
gel filtration
200000
-
Yersinia enterolytica
-
gel filtration
additional information
-
-
the enzyme shows extensive sequence homology and functional similarities in the active site of mercuric reductase and nicotinamide disulfide oxidoreductase
additional information
-
-
nucleotide sequence of the gene encoding mercuric reductase
SUBUNITS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
?
-
x * 69000, SDS-PAGE
?
-
x * 66200, recombinant His-tagged MerA, SDS-PAGE
?
-
x * 69000, SDS-PAGE
-
dimer
-
1 * 56000 + 1 * 62000, SDS-PAGE
dimer
-
2 * 56000, SDS-PAGE
dimer
-
1 * 58000 + 1 * 50400, SDS-PAGE
dimer
-
x * 54000 + x * 62000, SDS-PAGE
dimer
-
1 * 54000 + 1 * 69000, SDS-PAGE
dimer
Acidithiobacillus ferrooxidans TFI 29
-
x * 54000 + x * 62000, SDS-PAGE
-
dimer
Azotobacter chroococcum SS2
-
1 * 54000 + 1 * 69000, SDS-PAGE
-
dimer
Pseudomonas aeruginosa PAO9501
-
1 * 56000 + 1 * 62000, SDS-PAGE
-
dimer
Pseudomonas aeruginosa PAO9501 (pVS1)
-
1 * 58000 + 1 * 50400, SDS-PAGE
-
homodimer
-
2 * 50000, SDS-PAGE
monomer
-
1 * 58000, SDS-PAGE
trimer
Yersinia enterolytica
-
3 * 70000, SDS-PAGE
trimer
-
3 * 62000
trimer
-
3 * 65000, SDS-PAGE
trimer
Yersinia enterolytica 138A14
-
3 * 70000, SDS-PAGE
-
monomer
Penicillium sp. MR-2
-
1 * 58000, SDS-PAGE
-
additional information
Yersinia enterolytica
-
along with ageing, as well as limited proteolytic digestion, the enzyme evolves to give a dimeric molecule of 105000 Da composed of two identical subunits of 52000 Da
additional information
-
redox-active Cys residues at the active site
additional information
-
N-terminal domain NmerA participates in acquisition and delivery of Hg2+ to the catalytic core during thr reduction catalyzed by full-length enzyme
additional information
-
N-terminal domain NmerA participates in acquisition and delivery of Hg2+ to the catalytic core during thr reduction catalyzed by full-length enzyme
-
additional information
Yersinia enterolytica 138A14
-
along with ageing, as well as limited proteolytic digestion, the enzyme evolves to give a dimeric molecule of 105000 Da composed of two identical subunits of 52000 Da
-
Crystallization/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
hanging-drop vapor-diffusion method
-
TEMPERATURE STABILITY
TEMPERATURE STABILITY MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
80
-
Yersinia enterolytica
-
15 min, 15% loss of activity
100
-
Yersinia enterolytica
-
15 min, complete inactivation
GENERAL STABILITY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
stable to repeated freeze-thaw cycles
-
immobilization of the enzyme appears to significantly enhance storage stability
-
operational stability: after 1.5 h decline of activity up to 20%
-
OXIDATION STABILITY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
activated enzyme appears to be stable under anaerobic conditions and eventually returns to the original level of activity in the presence of oxygen. The activated state seems to be stabilized by 1mM cysteine.
-
438069
STORAGE STABILITY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
4C, 50 mM potassium phosphate buffer, pH 7.2, 0.5 mM EDTA, 1% 2-mercaptoethanol, half-life of soluble enzyme is 3 weeks, immobilized enzyme shows large decline at the beginning and almost no further decrease of activity after 3 weeks
-
Purification/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
recombinant His-tagged MerA from Escherichia coli strain BL21(DE3)Plys by nickel affinity chromatography
-
purification of the major 14C-labeled peptide from a tryptic digestion of labeled mercuric reductase
-
recombinant enzyme
-
recombinant MerA catalytic core and NmerA proteins from Escherichia coli strain XL-1 Blue by anion exchange chromatography and gel filtreation, and separation by affinity chromatography
E0XF09
-
Yersinia enterolytica
-
Cloned/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
cloned and expressed constitutively in Escherichia coli
-
merA, DNA and amino acid sequence determination of genes from bacteria isolated from surface and sub-surface floodplain soil, phylogenetic analysis, overview
-
expression in Escherichia coli
-
subcloning and expression in strain TG2, bacterial two hybrid assays are performed in strain BTH101
-
gene merA, recombinant expression in transgenoc Nicotiana tabacum cv. Xanthium plants using gene transfer by Agrobacterium tumefaciens. Transgenic tobacco expressing merA volatilizes significantly more mercury than wild-type plants. Subcloning in Escherichia coli strains DH5alpha and BL21(DE3)
Q9WTI5
plasmid transfer to mercury sensitive Escherichia coli strain DH5alpha, overexpression of gene merA as His-tagged protein in Escherichia coli BL21(DE3)Plys cells
-
gene merA and mer operon, expression of MerA catalytic core and NmerA proteins in Escherichia coli strain XL-1 Blue
E0XF09
merA, DNA and amino acid sequence determination of genes from bacteria isolated from surface and sub-surface floodplain soil, phylogenetic analysis, overview
-
EXPRESSION
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
transcriptional level of merA increased 157fold and 255 fold after 30 min after 60 min of incubation with 6 microM HgCl2+, respectively; transcriptional level of merA increased 197fold after incubation with 1 microM CdCl2+
-
transcriptional level of merA increased 30fold and 45fold after treatment with 10 microM ZnCl2+ and 30 microM ZnCl2+, respectively
-
transcriptional level of merA increased 6, 10, and 20fold after treatment with 5, 10, and 20 microM CdSO4 2+, respectively
-
transcriptional level of merA increased 6, 10, and 20fold after treatment with 5, 10, and 20 microM CdSO4 2+, respectively
-
-
ENGINEERING
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
C628A
-
HgX2 substrates with small ligands can rapidly access the redox-active cysteines in the absence of the C-terminal cysteines, but those with large ligands require the C-terminal cysteines for rapid access. The C-terminal cysteines play a critical role in removing the high-affinity ligands before Hg(II) reaches the redox-active cysteines
Y264F
-
Km-value for Hg2+ is 5fold lower compared to the Km-value of the wild-type enzyme, turn-over number is reduced by 164fold
Y264F/Y605F
-
Km-value for Hg2+ is 5fold lower than the Km-value of the wild-type enzyme, turnover-number is reduced by 1091fold
Y605F
-
Km-value for Hg2+ is 1.3fold higher compared to the Km-value of the wild-type enzyme, turnover-number is reduced by 6.3fold
C628A
-
HgX2 substrates with small ligands can rapidly access the redox-active cysteines in the absence of the C-terminal cysteines, but those with large ligands require the C-terminal cysteines for rapid access. The C-terminal cysteines play a critical role in removing the high-affinity ligands before Hg(II) reaches the redox-active cysteines
-
Y264F
-
Km-value for Hg2+ is 5fold lower compared to the Km-value of the wild-type enzyme, turn-over number is reduced by 164fold
-
Y264F/Y605F
-
Km-value for Hg2+ is 5fold lower than the Km-value of the wild-type enzyme, turnover-number is reduced by 1091fold
-
Y605F
-
Km-value for Hg2+ is 1.3fold higher compared to the Km-value of the wild-type enzyme, turnover-number is reduced by 6.3fold
-
C558A
-
mutation results in a total disruption of the Hg(II) detoxification pathway in vivo, compared to wild-type enzyme the mutant shows a 20fold reduction in turnover number and a 10fold increase in Km
C559A
-
mutation results in a total disruption of the Hg(II) detoxification pathway in vivo, compared to wild-type enzyme less than a 2fold reduction in turnover number and an increase in Km-value of 4-5fold
Y605H
-
24fold decrease in turnover number and a 15fold decrease in Km-value
C11A
-
site-directed mutagenesis of NmerA residue of the metal binding site
C14A
-
site-directed mutagenesis of NmerA residue of the metal binding site
C629A
-
HgX2 substrates with small ligands can rapidly access the redox-active cysteines in the absence of the C-terminal cysteines, but those with large ligands require the C-terminal cysteines for rapid access. The C-terminal cysteines play a critical role in removing the high-affinity ligands before Hg(II) reaches the redox-active cysteines
additional information
-
cloning and expression of catalytic core and N-terminal domain of enzyme as separate proteins. the N-terminal domain NmerA is a stable, soluble protein that binds 1 Hg2+ per domain and delivers it to the catalytic core at kinetically competent rates
C629A
-
HgX2 substrates with small ligands can rapidly access the redox-active cysteines in the absence of the C-terminal cysteines, but those with large ligands require the C-terminal cysteines for rapid access. The C-terminal cysteines play a critical role in removing the high-affinity ligands before Hg(II) reaches the redox-active cysteines
-
additional information
-
cloning and expression of catalytic core and N-terminal domain of enzyme as separate proteins. the N-terminal domain NmerA is a stable, soluble protein that binds 1 Hg2+ per domain and delivers it to the catalytic core at kinetically competent rates
-
Y62F
-
site-directed mutagenesis of NmerA residue of the metal binding site
additional information
-
constitutive expression of enzyme in Pseudomonas putida results in a broad spectrum mercury resistance
APPLICATION
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
environmental protection
-
detoxification of mercury by immobilized mercuric reductase
environmental protection
Escherichia coli PWS1
-
detoxification of mercury by immobilized mercuric reductase
-
environmental protection
-
application of the immobilized mercuric reductase for continuous treatment of Hg(II)-containing water in a fixed bed reactor
environmental protection
Pseudomonas putida KT2442::mer-73
-
application of the immobilized mercuric reductase for continuous treatment of Hg(II)-containing water in a fixed bed reactor
-