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Literature summary for 1.16.3.1 extracted from

  • Alaleona, F.; Franceschini, S.; Ceci, P.; Ilari, A.; Chiancone, E.
    Thermosynechococcus elongatus DpsA binds Zn(II) at a unique three histidine-containing ferroxidase center and utilizes O2 as iron oxidant with very high efficiency, unlike the typical Dps proteins (2010), FEBS J., 277, 903-917.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
gene tll2470 or dpsA-Te, expression as soluble His-tagged protein in Escherichia coli strain BL21(DE3) Thermosynechococcus vestitus

Crystallization (Commentary)

Crystallization (Comment) Organism
purified recombinant getagged DpsA-Te, 0.001 ml of 10 mg/ml protein in 20 mM Tris-HCl, pH 7.5, is mixed with 0.001 ml of reservoir solution containing 12% w/v PEG 8000 in 0.1 m MES, pH 6.0, 2 weeks, X-ray diffraction structure determination and analysis at 2.4 A resolution, molecular replacement Thermosynechococcus vestitus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
additional information iron oxidation and incorporation kinetics, overview Thermosynechococcus vestitus

Localization

Localization Comment Organism GeneOntology No. Textmining
thylakoid membrane possible localization of the protein at the thylakoid membranes due to presence of a long hydrophobic N-terminal tail Thermosynechococcus vestitus 42651
-

Metals/Ions

Metals/Ions Comment Organism Structure
Zn2+ DpsA-Te contains two Zn2+ bound at the ferroxidase center. The latter Zn2+ is displaced by incoming iron, such that Zn(II)-Fe(III) complexes are formed upon oxidation Thermosynechococcus vestitus

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
20900
-
12 * 20900, about, sequence calculation, three-dimensional structure analysis of DspA-Te, the subunits forming the pores at the ferritin-like interfaces have a slightly different orientation with respect to the three-fold symmetry axes than in the other Dps structures, overview. DpsA-Te ferroxidase center is unique, owing to the presence of a His78 in place of the canonical Asp metal ligand Thermosynechococcus vestitus

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
4 Fe2+ + 4 H+ + O2 Thermosynechococcus vestitus
-
4 Fe3+ + 2 H2O
-
?

Organism

Organism UniProt Comment Textmining
Thermosynechococcus vestitus Q8DL82 two Dps proteins, DpsA-Te and Dps-Te, encoded by the two genes tll2470 and tll0614 or dpsA-Te and dps-Te, respectively
-

Purification (Commentary)

Purification (Comment) Organism
recombinant His-tagged protein from Escherichia coli strain BL21(DE3) by heat treatment at 75°C for 10 min, dialysis, anion exchange chromatography, and affinity chromatography, followed by cleavage of the His-tag Thermosynechococcus vestitus

Reaction

Reaction Comment Organism Reaction ID
4 Fe(II) + 4 H+ + O2 = 4 Fe(III) + 2 H2O reaction mechanism, overview. Two reaction steps: 1. 2 Fe2+ O2 + 2 H+ = 2 Fe3+ + H2O2 and 2. H2O2 + 2 Fe2+ + 2 H+ = 2 Fe3+ + 2 H2O. The second step is rate-limiting Thermosynechococcus vestitus

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
4 Fe2+ + 4 H+ + O2
-
Thermosynechococcus vestitus 4 Fe3+ + 2 H2O
-
?

Subunits

Subunits Comment Organism
dodecamer 12 * 20900, about, sequence calculation, three-dimensional structure analysis of DspA-Te, the subunits forming the pores at the ferritin-like interfaces have a slightly different orientation with respect to the three-fold symmetry axes than in the other Dps structures, overview. DpsA-Te ferroxidase center is unique, owing to the presence of a His78 in place of the canonical Asp metal ligand Thermosynechococcus vestitus

Synonyms

Synonyms Comment Organism
Dps-Te
-
Thermosynechococcus vestitus
DpsA
-
Thermosynechococcus vestitus
DpsA-Te
-
Thermosynechococcus vestitus

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
20
-
standard assay at Thermosynechococcus vestitus

Temperature Range [°C]

Temperature Minimum [°C] Temperature Maximum [°C] Comment Organism
10 50 assay range Thermosynechococcus vestitus

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
100
-
completely stable at pH 3.0-7.0, but complete and irreversibe degeneration at 75-80°C Thermosynechococcus vestitus

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7
-
assay at Thermosynechococcus vestitus

pH Stability

pH Stability pH Stability Maximum Comment Organism
2 7 at pH 2.0, the enzyme structure is stable at room temperature, but completely and irreversibly degenerates at 75-80°C Thermosynechococcus vestitus

General Information

General Information Comment Organism
additional information DpsA-Te ows a unique substitution of a metal ligand at the A-site, i.e. His78 in place of the canonical Asp, and a His164 in place of a hydrophobic residue at a metal-coordinating distance in the B-site. In contrast to the typical behavior of Dps proteins, where Fe2+ oxidation by H2O2 is about 100fold faster than by O2, in DpsA-Te the ferroxidation efficiency of O2 is very high and resembles that of H2O2. DpsA-Te contains two Zn2+ bound at the ferroxidase center. The latter Zn2+ is displaced by incoming iron, such that Zn(II)-Fe(III) complexes are formed upon oxidation Thermosynechococcus vestitus
physiological function DpsA-Te can protect DNA molecules against Fe(II)-mediated and H2O2-mediated damage. Dps-Te and DpsA-Te, together with ferritin, play an important role in alleviating the toxic effects of reactive oxygen species, physiological basis of the coexistence of two Dps proteins in the organism, overview Thermosynechococcus vestitus