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Literature summary for 1.16.3.2 extracted from

  • Bou-Abdallah, F.; Yang, H.; Awomolo, A.; Cooper, B.; Woodhall, M.R.; Andrews, S.C.; Chasteen, N.D.
    Functionality of the three-site ferroxidase center of Escherichia coli bacterial ferritin (EcFtnA) (2014), Biochemistry, 53, 483-495 .
    View publication on PubMedView publication on EuropePMC
Search for more literature for 1.16.3.2

Protein Variants

Protein Variants Comment Organism
E126A site-directed mutagenesis, elimination of C-site ligands as in variants E126A, E49A and E130A causes a decrease in the Fe(II)/O2 stoichiometry from approx. 3 to approx. 2 for the first 48 Fe(II) added to the protein. The C-site variants (particularly E49A and E126A) fully regenerate their initial ferroxidase activity within a few hours compared to a day or so required for wild-type EcFtnA Escherichia coli
E130A site-directed mutagenesis, elimination of C-site ligands as in variants E126A, E49A and E130A causes a decrease in the Fe(II)/O2 stoichiometry from approx. 3 to approx. 2 for the first 48 Fe(II) added to the protein Escherichia coli
E17A site-directed mutagenesis, elimination of either A- or B-site ligands of EcFtnA, as in variants H53A, E17A and E94A, increases the Fe(II)/O2 stoichiometry from approx. 3 to approx. 4 Escherichia coli
E49A site-directed mutagenesis, elimination of C-site ligands as in variants E126A, E49A and E130A causes a decrease in the Fe(II)/O2 stoichiometry from approx. 3 to approx. 2 for the first 48 Fe(II) added to the protein. The C-site variants (particularly E49A and E126A) fully regenerate their initial ferroxidase activity within a few hours compared to a day or so required for wild-type EcFtnA Escherichia coli
E94A site-directed mutagenesis, elimination of either A- or B-site ligands of EcFtnA, as in variants H53A, E17A and E94A, increases the Fe(II)/O2 stoichiometry from approx. 3 to approx. 4 Escherichia coli
H53A site-directed mutagenesis, elimination of either A- or B-site ligands of EcFtnA, as in variants H53A, E17A and E94A, increases the Fe(II)/O2 stoichiometry from approx. 3 to approx. 4 Escherichia coli
Y24F site-directed mutagenesis, variant Y24F is a kinetically competent protein capable of forming a diFe(III) peroxo complex upon addition of the first 48 Fe(II) to the protein with rate parameters similar to wild-type EcFtnA Escherichia coli

Metals/Ions

Metals/Ions Comment Organism Structure
Mn2+ can bind to the enzyme, structure analysis Escherichia coli
additional information EcFtnA is a non-heme bacterial ferritin. in addition to the conserved A- and B-sites of the diiron ferroxidase center, EcFtnA has a third iron-binding site (the C-site) that is near the diiron site. Analysis of metal binding sites, overview Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
2 Fe(II) + H2O2 + 2 H2O Escherichia coli
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 2 [FeO(OH)] + 4 H+
-
 ?
2 Fe(II) + O2 + 4 H2O Escherichia coli
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 2 [FeO(OH)] + 4 H+ + H2O2
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 ?

Organism

Organism UniProt Comment Textmining
Escherichia coli P0A998
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-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2 Fe(II) + H2O2 + 2 H2O
-
 Escherichia coli 2 [FeO(OH)] + 4 H+
-
 ?
2 Fe(II) + O2 + 4 H2O
-
 Escherichia coli 2 [FeO(OH)] + 4 H+ + H2O2
-
 ?
additional information in addition to the conserved A- and B-sites of the diiron ferroxidase center, EcFtnA has a third iron-binding site (the C-site) that is near the diiron site. The enzyme requires fully functional A- and B-sites for high ferroxidase activity. There are multiple iron-oxidation pathways in EcFtnA with O2 and H2O2 as oxidants. While H2O2 is a product of dioxygen reduction in EcFtnA and oxidation occurs with a stoichiometry of Fe(II)/O2 about 3:1, most of the H2O2 produced is consumed in subsequent reactions with a 2:1 Fe(II)/H2O2 stoichiometry, thus suppressing hydroxyl radical formation. One of the unique properties of EcFtnA is its unusual Fe(II)/O2 oxidation stoichiometry of approx. 3 Escherichia coli ?
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 ?

Synonyms

Synonyms Comment Organism
EcFtnA
-
 Escherichia coli
ferritin
-
 Escherichia coli
non-heme bacterial ferritin
-
 Escherichia coli

General Information

General Information Comment Organism
physiological function ferritins use Fe2+ and either dioxygen or hydrogen peroxide as oxidants to form a hydrous ferric oxide mineral core. The enzyme EcFtnA displays H2O2 detoxification properties whereby two Fe2+ are oxidized per H2O2 reduced. The enzyme requires fully functional A- and B-sites for high ferroxidase activity. The mechanism of iron oxidation and deposition in EcFtnA is complex with multiple reactions involving the A-, B-, and C-sites of the ferroxidase center, the mineral surface and both O2 and H2O2 as oxidants Escherichia coli