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Literature summary for 1.11.1.B2 extracted from

  • Mubarak, M.; Gerard, E.; Blanford, C.; Hay, S.; De Visser, S.
    How do vanadium chloroperoxidases generate hypochlorite from hydrogen peroxide and chloride? A computational study (2020), ACS Catal., 10, 14067-14079 .
No PubMed abstract available
Search for more literature for 1.11.1.B2

Crystallization (Commentary)

Crystallization (Comment) Organism
enzyme crystal structure analysis, PDB ID 1IDQ. Computational modeling is performed using a combination of molecular mechanics (MM), molecular dynamics (MD), and density functional theory (DFT) calculations on cluster models Curvularia inaequalis

Metals/Ions

Metals/Ions Comment Organism Structure
Vanadium the active-site vanadium(V) ion is linked to the protein via a histidine residue. Vanadium is a spectator ion that does not change its oxidation state during the reaction mechanism but holds and positions the H2O2 substrate and guides its proton-relay steps through its oxo and hydroxo ligands Curvularia inaequalis

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
RH + Cl- + H2O2 + H+ Curvularia inaequalis
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 RCl + 2 H2O
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 ?

Organism

Organism UniProt Comment Textmining
Curvularia inaequalis P49053 Helminthosporium inaequale
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Reaction

Reaction Comment Organism Reaction ID
RH + Cl- + H2O2 + H+ = RCl + 2 H2O biosynthesis of hypochlorite proceeds in two steps: H2O2 activation on the vanadium center to form an end-on V(V)-hydroperoxo complex, followed by OH+ transfer from hydroperoxo to chloride on the vanadium center to form hypochlorite. The initial reaction starts with a proton transfer from H2O2 to the equatorial OH group of the VV(O)2(OH)2- active site, followed by hydroperoxo binding and water release to form the highly stable vanadium-hydroperoxo-dioxo-hydroxo complex. A further proton transfer from an active-site His or Lys residue can lead to the vanadium-peroxo-hydroxo-oxo complex, which is assign as a dead-end complex unable to react further to hypochlorite products. The mechanisms are considered under various protonation state, and the most effective is the one with His404 singly protonated. Vanadium is a spectator ion that does not change its oxidation state during the reaction mechanism but holds and positions the H2O2 substrate and guides its proton-relay steps through its oxo and hydroxo ligands. The reaction is highly sensitive to local changes in the protonation state. The oxygen atom of HOCl exclusively derives from H2O2 Curvularia inaequalis
a

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information catalytic cycle and function of the vanadium atom in the reaction mechanism, computational study using large cluster model complexes, possible pathways, and active-site protonation states, overview Curvularia inaequalis ?
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RH + Cl- + H2O2 + H+
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 Curvularia inaequalis RCl + 2 H2O
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 ?

Synonyms

Synonyms Comment Organism
vanadium chloroperoxidase
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 Curvularia inaequalis
vanadium haloperoxidase
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 Curvularia inaequalis

Cofactor

Cofactor Comment Organism Structure
vanadate cofactor
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 Curvularia inaequalis

General Information

General Information Comment Organism
additional information the active-site vanadium(V)-trioxo-hydroxo species is bound to His496. It is in trigonal bipyramidal symmetry and held in position with a string of polar (hydrogen-bonding) residues including those of Lys353, Arg360, Ser402, His404, and Arg490. As such, the active site is arranged in a tight hydrogen-bonding network, and a proton relay machinery appears to be available that can bring external protons into the active site to participate in the catalytic cycle. Active-site structure, overview. Computational modeling is performed using a combination of molecular mechanics (MM), molecular dynamics (MD), and density functional theory (DFT) calculations on cluster models. One narrow channel entering the active-site pocket with a cavity on the surface, where an organic substrate can attach. The channel connects the vanadium active site with the protein surface through the space in between the His404 and Arg490 residues. Consequently, hydrogen peroxide is inserted into the cavity at the end of the channel. Analysis of the catalytic cycle Curvularia inaequalis
physiological function vanadium haloperoxidases are one of the few enzymes in nature that utilize a vanadium center and catalyze the halogenation of substrates through the biosynthesis of hypohalite. Vanadium chloroperoxidases (VCPOs) bind and activate hydrogen peroxide and in a reaction with chloride convert it into hypochlorite as a precursor for a substrate chlorination reaction Curvularia inaequalis