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Literature summary for 3.5.2.17 extracted from

  • French, J.B.; Ealick, S.E.
    Structural and kinetic insights into the mechanism of 5-hydroxyisourate hydrolase from Klebsiella pneumoniae (2011), Acta Crystallogr. Sect. D, 67, 671-677.
    View publication on PubMedView publication on EuropePMC
Search for more literature for 3.5.2.17

Cloned(Commentary)

Cloned (Comment) Organism
expression in Escherichia coli Klebsiella pneumoniae

Crystallization (Commentary)

Crystallization (Comment) Organism
to 1.8 A resolution, and modeling of substrate 5-hydroxyisourate into the active site. The four chains of the enzyme come together to form a homotetramer with 222 symmetry. The tetramer is a dimer of dimers, with two protomers arranged to create an extended beta-sheet that makes up the dimer–dimer interface Klebsiella pneumoniae

Protein Variants

Protein Variants Comment Organism
H7N dramatic decrease in activity Klebsiella pneumoniae
H92N dramatic decrease in activity Klebsiella pneumoniae
R41K about 90% decrease in activity Klebsiella pneumoniae
S108A about 50% decrease in activity Klebsiella pneumoniae

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.093
-
 5-hydroxyisourate mutant S108A, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
0.103
-
 5-hydroxyisourate wild-type, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
0.195
-
 5-hydroxyisourate mutant R41K, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
0.43
-
 5-hydroxyisourate mutant H92N, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
4.4
-
 5-hydroxyisourate mutant H7N, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae

Organism

Organism UniProt Comment Textmining
Klebsiella pneumoniae A6T926
-
-
Klebsiella pneumoniae ATCC 700721 A6T926
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
5-hydroxyisourate + H2O
-
 Klebsiella pneumoniae 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline
-
 ?
5-hydroxyisourate + H2O
-
 Klebsiella pneumoniae ATCC 700721 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline
-
 ?
additional information reaction is likely to be initiated by a water molecule that is first activated by deprotonation. The hydrogen-bonding interactions between the water molecule and residues His7 and His92 would serve to orient the water ideally for attack at C6 of the purine ring. The C-terminal serine residue, Ser108, is in position to form a hydrogen bond to His7 and may indirectly participate in catalysis by inductively activating this residue. Deprotonation of the water by His7 creates a hydroxide nucleophile that attacks C6 of the purine ring, leading to a tetrahedral oxyanion intermediate. The charge on the resulting oxyanion would be stabilized by the positively charged guanidinium group of Arg41. Arg41 from the neighboring chain helps to stabilize the charge on the oxyanion intermediate.Collapse of the oxyanion would then lead to ring opening, with the final proton coming from the nearby Arg41. The original proton abstracted from a water molecule by His7 would then be transferred to Arg41 to complete the catalytic cycle Klebsiella pneumoniae ?
-
 ?
additional information reaction is likely to be initiated by a water molecule that is first activated by deprotonation. The hydrogen-bonding interactions between the water molecule and residues His7 and His92 would serve to orient the water ideally for attack at C6 of the purine ring. The C-terminal serine residue, Ser108, is in position to form a hydrogen bond to His7 and may indirectly participate in catalysis by inductively activating this residue. Deprotonation of the water by His7 creates a hydroxide nucleophile that attacks C6 of the purine ring, leading to a tetrahedral oxyanion intermediate. The charge on the resulting oxyanion would be stabilized by the positively charged guanidinium group of Arg41. Arg41 from the neighboring chain helps to stabilize the charge on the oxyanion intermediate.Collapse of the oxyanion would then lead to ring opening, with the final proton coming from the nearby Arg41. The original proton abstracted from a water molecule by His7 would then be transferred to Arg41 to complete the catalytic cycle Klebsiella pneumoniae ATCC 700721 ?
-
 ?

Synonyms

Synonyms Comment Organism
HIU
-
 Klebsiella pneumoniae

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.35
-
 5-hydroxyisourate mutant H92N, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
0.8
-
 5-hydroxyisourate mutant H7N, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
34.7
-
 5-hydroxyisourate mutant R41K, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
81
-
 5-hydroxyisourate mutant S108A, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
172
-
 5-hydroxyisourate wild-type, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
0.18
-
 5-hydroxyisourate mutant H7N, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
0.82
-
 5-hydroxyisourate mutant H92N, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
180
-
 5-hydroxyisourate mutant R41K, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
870
-
 5-hydroxyisourate mutant S108A, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae
1700
-
 5-hydroxyisourate wild-type, pH 7.6, temperature not specified in the publication Klebsiella pneumoniae