Literature summary for 1.16.1.1 extracted from

Sayed, A.; Ghazy, M.A.; Ferreira, A.J.; Setubal, J.C.; Chambergo, F.S.; Ouf, A.; Adel, M.; Dawe, A.S.; Archer, J.A.; Bajic, V.B.; Siam, R.; El-Dorry, H.
A novel mercuric reductase from the unique deep brine environment of Atlantis II in the Red Sea (2014), J. Biol. Chem., 289, 1675-1687.

Search for more literature for 1.16.1.1

Cloned(Commentary)

Cloned (Comment)	Organism
gene merA, the MerA protein is encoded by the mer operon on transposon Tn501, DNA and amino acid sequence determination and analysis, sequence comparisons and phylogenetic analysis	uncultured prokaryote

Protein Variants

Protein Variants	Comment	Organism
E133G/E134G	site-directed mutagenesis, the mutant shows altered salt and metal resistance and temperature stability compared to the wild-type enzyme	uncultured prokaryote
E15A/E16A	site-directed mutagenesis, the mutant shows altered salt and metal resistance and temperature stability compared to the wild-type enzyme	uncultured prokaryote
E515A/E516A	site-directed mutagenesis, the mutant shows altered salt and metal resistance and temperature stability compared to the wild-type enzyme	uncultured prokaryote
E545A/E546A	site-directed mutagenesis, the mutant shows salt and metal resistance and temperature stability similar to the wild-type enzyme	uncultured prokaryote
K432L/P433D/A434L/R435T	site-directed mutagenesis, the mutant shows salt and metal resistance and temperature stability similar to the wild-type enzyme	uncultured prokaryote
K432L/P433D/A434L/R435T/K465D/V466S/G467R/K468T/F469L/P470T	site-directed mutagenesis, the mutant shows salt and metal resistance and temperature stability similar to the wild-type enzyme	uncultured prokaryote
additional information	mutations to substitute residues from the ATII-LCL MerA to their corresponding amino acids in the soil enzyme, overview	uncultured prokaryote

Inhibitors

Inhibitors	Comment	Organism	Structure
Hg2+	slight inhibition of the ATII-LCL enzyme	uncultured prokaryote

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
additional information	-	additional information	kinetics of wild-type and mutant enzymes, overview	uncultured prokaryote

Metals/Ions

Metals/Ions	Comment	Organism	Structure
additional information	the mercuric reductase is functional in high salt and resistant to high concentrations of Hg2+	uncultured prokaryote

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
Hg + NADP+ + H+	uncultured prokaryote	-	Hg2+ + NADPH	-	r

Organism

Organism	UniProt	Comment	Textmining
uncultured prokaryote	V5TDP2	from the unique deep brine environment of Atlantis II in the Red Sea, lower convective layer, gene merA	-

Source Tissue

Source Tissue	Comment	Organism	Textmining
additional information	the organism is grown in the lower convective layer of the brine pool at Atlantis II Deep in the Red Sea, with a maximum depth of over 2000 m, the pool is characterized by acidic pH 5.3, high temperature 68°C, , salinity of 26%, low light levels, anoxia, and high concentrations of heavy metals	uncultured prokaryote	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
Hg + NADP+ + H+	-	uncultured prokaryote	Hg2+ + NADPH	-	r

Subunits

Subunits	Comment	Organism
homodimer	each monomer contributes one active site, made up of a pair of redox-active cysteines, to a catalytic core located at the dimer interface, three-dimensional structure homology modeling, overview	uncultured prokaryote

Synonyms

Synonyms	Comment	Organism
mercuric reductase	-	uncultured prokaryote

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
37	-	assay at	uncultured prokaryote

Temperature Stability [°C]

Temperature Stability Minimum [°C]	Temperature Stability Maximum [°C]	Comment	Organism
additional information	-	the mercuric reductase is stable at high temperatures	uncultured prokaryote
60	-	10 min, 80% activity remaining	uncultured prokaryote
75	-	10 min, 50% inactivation	uncultured prokaryote

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
7.4	-	assay at	uncultured prokaryote

Cofactor

Cofactor	Comment	Organism	Structure
FAD	-	uncultured prokaryote
additional information	the enzymes contains FAD, utilizes NADPH as an electron donor, and requires an excess of exogenous thiols for activity	uncultured prokaryote
NADP+	-	uncultured prokaryote
NADPH	-	uncultured prokaryote

IC50 Value

IC50 Value	IC50 Value Maximum	Comment	Organism	Inhibitor	Structure
0.27	-	pH 7.4, 37°C	uncultured prokaryote	Hg2+

General Information

General Information	Comment	Organism
additional information	the two acidic residues immediately adjacent to the NmerA metal-binding motif in the ATII-LCL protein have a direct effect on both the halophilicity and catalytic efficiency of the enzyme. Presumably, by increasing the efficiency of delivery of Hg2 ions to the catalytic core for reduction, they also help the host to cope with the high concentrations of mercury present in its hypersaline environment	uncultured prokaryote
physiological function	the mercuric reductase is functional in high salt, stable at high temperatures, resistant to high concentrations of Hg2, and efficiently detoxifies Hg2 in vivo. Mercuric ion reductase catalyzes the reduction of Hg2+ to Hg0, which is volatile and can be disposed of nonenzymatically	uncultured prokaryote

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Release 2023.1 (January 2023)