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Literature summary for 1.13.11.15 extracted from

  • Mbughuni, M.M.; Meier, K.K.; Muenck, E.; Lipscomb, J.D
    Substrate-mediated oxygen activation by homoprotocatechuate 2,3-dioxygenase: intermediates formed by a tyrosine 257 variant (2012), Biochemistry, 51, 8743-8754.
    View publication on PubMedView publication on EuropePMC

Cloned(Commentary)

Cloned (Comment) Organism
recombinant expression of wild-type and mutant Y257F enzymes Brevibacterium fuscum

Protein Variants

Protein Variants Comment Organism
Y257F site-directed mutagenesis, the two reaction intermediates formed with the mutant enzyme differ from that of the the wild-type enzyme, substrate binds tightly to Y257F, the intense Mössbauer spectrum of suggests the intermediate is most likely an HPCA quinone-FeII-(hydro)peroxo species. Steady-state and transient kinetic analyses show that steps of the catalytic cycle are slowed by as much as 100fold by the mutation due to failure of Y257F to facilitate the observed distortion of the bound HPCA that is proposed to promote transfer of one electron to O2, Mössbauer spectral analysis, overview Brevibacterium fuscum

Metals/Ions

Metals/Ions Comment Organism Structure
Fe2+ the catalytic Fe2+ is active site bound, electron transfer from the chelated aromatic substrate through the Fe2+ to O2 gives both substrates radical character promoting reaction between the substrates to form an alkylperoxo intermediate as the first step in aromatic ring cleavage Brevibacterium fuscum

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
3,4-dihydroxyphenylacetate + O2 Brevibacterium fuscum
-
2-hydroxy-5-carboxymethylmuconate semialdehyde
-
?

Organism

Organism UniProt Comment Textmining
Brevibacterium fuscum
-
-
-

Purification (Commentary)

Purification (Comment) Organism
recombinant wild-type and mutant Y257F enzymes by a procedure including anion exchange chromatography Brevibacterium fuscum

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
3,4-dihydroxyphenylacetate + O2
-
Brevibacterium fuscum 2-hydroxy-5-carboxymethylmuconate semialdehyde
-
?
3,4-dihydroxyphenylacetate + O2 Mössbauer spectra of the reaction intermediates trapped by rapid freeze quench show that both intermediates contain Fe2+. The lack of a chromophore characteristic of a quinone or semiquinone form of HPCA, the presence of Fe2+, and the low O2 affinity suggests that is an HPCA-FeII-O2 complex with little electron delocalization onto the O2 Brevibacterium fuscum 2-hydroxy-5-carboxymethylmuconate semialdehyde
-
?
4-nitrocatechol + O2 a slow alternative substrate Brevibacterium fuscum ?
-
?

Synonyms

Synonyms Comment Organism
FeHPCD
-
Brevibacterium fuscum
homoprotocatechuate 2,3-dioxygenase
-
Brevibacterium fuscum

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
4 22 assay at 4°C or 22°C Brevibacterium fuscum

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
5.5 7.5 assay at Brevibacterium fuscum

General Information

General Information Comment Organism
malfunction In mutant Y257F, steps of the catalytic cycle are slowed by as much as 100fold by the mutation compared to the wild-type enzyme due to failure of mutant Y257F to facilitate the observed distortion of the bound 3,4-dihydroxyphenylacetate that is proposed to promote transfer of one electron to O2, Steady-state and transient kinetic analyses Brevibacterium fuscum
additional information reaction mechanism and intermediate formation, Mössbauer spectral analysis of wild-type and Y257F mutant enzymes, detailed overview. Residue His200 is positioned to interact with both the substrate C4-OH substituent and the bound oxygen. It plays many roles including that of an acid-base catalyst to promote the Criegee rearrangement chemistry Brevibacterium fuscum