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Literature summary for 1.15.1.2 extracted from

  • Sousa, C.M.; Carpentier, P.; Matias, P.M.; Testa, F.; Pinho, F.; Sarti, P.; Giuffre, A.; Bandeiras, T.M.; Romao, C.V.
    Superoxide reductase from Giardia intestinalis structural characterization of the first SOR from a eukaryotic organism shows an iron centre that is highly sensitive to photoreduction (2015), Acta Crystallogr. Sect. D, 71, 2236-2247 .
    View publication on PubMed

Crystallization (Commentary)

Crystallization (Comment) Organism
purified enzyme, hanging drop vapour diffusion technique, mixing of 0.001 ml of 12 mg/ml protein solution in a 1:1 ratio with reservoir solution, and equilibration against 0.1 ml reservoir solution, method optimization, best crystals are obtained after 1 d in 24% v/v dioxane at protein:precipitant ratios of 0.002:0.0001, 0.0025:0.0001 and 0.003:0.0001 ml, 35% w/v glycerol is added to the cover slip to avoid dioxane evaporation, to a final volume of 0.006-0.010 ml, X-ray diffraction structure determination and analysis at 1.9-2.65 A resolution, modeling Giardia intestinalis

Metals/Ions

Metals/Ions Comment Organism Structure
Fe2+ a 1Fe-SOR, the iron centre is highly sensitive to photoreduction. The N-terminal loop of the protein, containing the characteristic EKHxP motif, reveals an unusually high flexibility regardless of the iron redox state. Each GiSOR monomer displays a solvent-exposed active site containing one Fe atom. The high solvent accessibility of the metal has been proposed to be important for the catalytic function of the enzyme, as it ensures easy access of superoxide anion to the active site and its prompt reduction to hydrogen peroxide. The Fe atom displays octahedral coordination geometry and is coordinated by residues located in loops connecting beta-strands: the imidazole rings of His19, His40, His46 and His102 in the equatorial plane, with the Cys99 S atom and one carboxylate O atom from Glu17 occupying the two axial positions Giardia intestinalis

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
superoxide + reduced acceptor + 2 H+ Giardia intestinalis
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H2O2 + oxidized acceptor
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?

Organism

Organism UniProt Comment Textmining
Giardia intestinalis V6TJK7
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-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
superoxide + reduced acceptor + 2 H+
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Giardia intestinalis H2O2 + oxidized acceptor
-
?

Subunits

Subunits Comment Organism
More enzyme structure modeling Giardia intestinalis

Synonyms

Synonyms Comment Organism
1Fe-SOR
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Giardia intestinalis
GiSOR
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Giardia intestinalis
SOR
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Giardia intestinalis

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
additional information
-
the thermal stability of the protein is significantly higher in 100 mM 3-(N-morpholino)-propanesulfonic acid (MOPS), pH 7.0, compared to 50 mM Tris-HCl, pH 7.5 Giardia intestinalis

General Information

General Information Comment Organism
additional information iron reduction does not lead to dissociation of glutamate from the catalytic metal or other structural changes, but the glutamate ligand undergoes X-ray-induced chemical changes, revealing high sensitivity of the GiSOR active site to X-ray radiation damage, enzyme structure modeling and structure comparisons Giardia intestinalis
physiological function superoxide reductase (SOR) affords protection from oxidative stress by reducing the superoxide anion to hydrogen peroxide Giardia intestinalis