1XZW

Sweet potato purple acid phosphatase/phosphate complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.238 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Phosphate forms an unusual tripodal complex with the Fe-Mn center of sweet potato purple acid phosphatase

Schenk, G.Gahan, L.R.Carrington, L.E.Mitic, N.Valizadeh, M.Hamilton, S.E.de Jersey, J.Guddat, L.W.

(2005) Proc.Natl.Acad.Sci.USA 102: 273-278

  • DOI: 10.1073/pnas.0407239102

  • PubMed Abstract: 
  • Purple acid phosphatases (PAPs) are a family of binuclear metalloenzymes that catalyze the hydrolysis of phosphoric acid esters and anhydrides. A PAP in sweet potato has a unique, strongly antiferromagnetically coupled Fe(III)-Mn(II) center and is di ...

    Purple acid phosphatases (PAPs) are a family of binuclear metalloenzymes that catalyze the hydrolysis of phosphoric acid esters and anhydrides. A PAP in sweet potato has a unique, strongly antiferromagnetically coupled Fe(III)-Mn(II) center and is distinguished from other PAPs by its increased catalytic efficiency for a range of activated and unactivated phosphate esters, its strict requirement for Mn(II), and the presence of a mu-oxo bridge at pH 4.90. This enzyme displays maximum catalytic efficiency (k(cat)/K(m)) at pH 4.5, whereas its catalytic rate constant (k(cat)) is maximal at near-neutral pH, and, in contrast to other PAPs, its catalytic parameters are not dependent on the pK(a) of the leaving group. The crystal structure of the phosphate-bound Fe(III)-Mn(II) PAP has been determined to 2.5-A resolution (final R(free) value of 0.256). Structural comparisons of the active site of sweet potato, red kidney bean, and mammalian PAPs show several amino acid substitutions in the sweet potato enzyme that can account for its increased catalytic efficiency. The phosphate molecule binds in an unusual tripodal mode to the two metal ions, with two of the phosphate oxygen atoms binding to Fe(III) and Mn(II), a third oxygen atom bridging the two metal ions, and the fourth oxygen pointing toward the substrate binding pocket. This binding mode is unique among the known structures in this family but is reminiscent of phosphate binding to urease and of sulfate binding to lambda protein phosphatase. The structure and kinetics support the hypothesis that the bridging oxygen atom initiates hydrolysis.


    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, School of Molecular and Microbial Sciences, University of Queensland, Brisbane 4072, Australia. schenk@uq.edu.au




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
purple acid phosphatase
A, B
426Ipomoea batatasGene Names: PAP1
EC: 3.1.3.2
Find proteins for Q9SE00 (Ipomoea batatas)
Go to UniProtKB:  Q9SE00
Small Molecules
Ligands 6 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN
Query on MN

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A, B
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
PO4
Query on PO4

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A, B
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
MAN
Query on MAN

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A, B
ALPHA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-PQMKYFCFSA-N
 Ligand Interaction
FUC
Query on FUC

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A, B
ALPHA-L-FUCOSE
C6 H12 O5
SHZGCJCMOBCMKK-SXUWKVJYSA-N
 Ligand Interaction
FE
Query on FE

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A, B
FE (III) ION
Fe
VTLYFUHAOXGGBS-UHFFFAOYSA-N
 Ligand Interaction
NAG
Query on NAG

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A, B
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.238 
  • Space Group: P 65 2 2
Unit Cell:
Length (Å)Angle (°)
a = 116.150α = 90.00
b = 116.150β = 90.00
c = 291.950γ = 120.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
Adxvdata processing
X-PLORphasing
X-PLORmodel building
X-PLORrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-12-14
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Non-polymer description, Version format compliance
  • Version 1.3: 2017-10-11
    Type: Refinement description