Any feedback?
Please rate this page
(literature.php)
(0/150)

BRENDA support

Literature summary for 3.1.3.8 extracted from

  • Boehm, K.; Herter, T.; Mueller, J.J.; Borriss, R.; Heinemann, U.
    Crystal structure of Klebsiella sp. ASR1 phytase suggests substrate binding to a preformed active site that meets the requirements of a plant rhizosphere enzyme (2010), FEBS J., 277, 1284-1296.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
expression of His-tagged wild-type PhyK and of mutant H25A PhyK in Escherichia coli strain C41 (DE3) Klebsiella sp.

Crystallization (Commentary)

Crystallization (Comment) Organism
native PhyK and inactive mutant H25A phytase PhyK, the latter with bound sulfate ions, hanging-drop vapor diffusion at 18°C, 5-6 weeks, for the wild-type enzyme: mixing of 6 mg/ml protein in 20 mM sodium acetate (pH 5.0), 50 mm NaCl with an equal volume of 4.0 M sodium formate, for mutant H25A: mixing of 0.0015 ml of protein in 25 mM sodium acetate pH 5.0, 60 mM NaCl and 1 mM tris-(2-carboxyethyl)phosphine with 0.0015 ml of 12% PEG 8000, 0.08 M (NH4)2SO4, 0.1 M sodium acetate and 1.5 mM phytate, 1 week, 22°C, X-ray diffraction structure determination and analysis at 1.7 A resolution, single-wavelength anomalous-diffraction phasing Klebsiella sp.

Protein Variants

Protein Variants Comment Organism
H25A inactive mutant Klebsiella sp.

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
additional information Klebsiella sp. phytase ASr1 acts primarily as a scavenger of phosphate groups locked in the phytic acid molecule ?
-
?
myo-inositol-1,2,3,4,5,6-hexakisphosphate + H2O Klebsiella sp. although the PhyK homolog AppA is biochemically characterized as a 6-phytase, a co-crystal structure shows the phytate 3-phosphate as scissile group in a similar position to in the active site of PhyK myo-inositol-1,2,4,5,6-pentakisphosphate + phosphate
-
?

Organism

Organism UniProt Comment Textmining
Klebsiella sp. Q84CN9
-
-

Purification (Commentary)

Purification (Comment) Organism
recombinant His-tagged wild-type PhyK and of mutant H25A PhyK from Escherichia coli strain C41 (DE3) by nickel affinity chromatography Klebsiella sp.

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information phytase ASr1 acts primarily as a scavenger of phosphate groups locked in the phytic acid molecule Klebsiella sp. ?
-
?
additional information substrate binding structure modelling, all six phosphate groups of phytate are involved in a hydrogen bond network connecting the substrate with PhyK, induced conformational changes upon substrate binding, overview Klebsiella sp. ?
-
?
myo-inositol-1,2,3,4,5,6-hexakisphosphate + H2O although the PhyK homolog AppA is biochemically characterized as a 6-phytase, a co-crystal structure shows the phytate 3-phosphate as scissile group in a similar position to in the active site of PhyK Klebsiella sp. myo-inositol-1,2,4,5,6-pentakisphosphate + phosphate
-
?
myo-inositol-1,2,3,4,5,6-hexakisphosphate + H2O although the PhyK homolog AppA is biochemically characterized as a 6-phytase, a co-crystal structure shows the phytate 3-phosphate as scissile group in a similar position to in the active site of PhyK Klebsiella sp. 1D-myo-inositol-1,2,4,5,6-pentakisphosphate + phosphate
-
?

Subunits

Subunits Comment Organism
More the ASR1 phytase polypeptide chain is organized into an alpha and an alpha,beta domain, and the active site is located in a positively charged cleft between the domains Klebsiella sp.

Synonyms

Synonyms Comment Organism
ASR1
-
Klebsiella sp.
HAP
-
Klebsiella sp.
histidine acid phosphatase
-
Klebsiella sp.
More phytase ASR1 is a member of the histidine-acid-phosphatase family, that shares two conserved active-site motifs, RHGXRXP and HD, and hydrolyzes metal-free phytate with pH optima in the acidic range Klebsiella sp.
PhyK
-
Klebsiella sp.

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
370
-
myo-inositol-1,2,3,4,5,6-hexakisphosphate pH not specified in the publication, temperature not specified in the publication Klebsiella sp.

General Information

General Information Comment Organism
additional information phytase ASR1 is a member of the histidine-acid-phosphatase family, that shares two conserved active-site motifs, RHGXRXP and HD, and hydrolyzes metal-free phytate with pH optima in the acidic range. Histidine-acid-phosphatases share a common two-step mechanism for catalysis. The reaction starts with a nucleophilic attack on the phosphoester bond by a conserved histidine in the long active-site motif. The histidine side chain from the conserved HD motif protonates the leaving group. The second step comprises hydrolysis of the resulting covalent phospho-histidine intermediate. Comparison of substrate binding of Klebsiella sp. ASR1 PhyK with Escherichia coli AppA phytase Klebsiella sp.

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
7900
-
myo-inositol-1,2,3,4,5,6-hexakisphosphate pH not specified in the publication, temperature not specified in the publication Klebsiella sp.