3TX0

Unphosphorylated Bacillus cereus phosphopentomutase in a P212121 crystal form


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.26 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.192 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Molecular Differences between a Mutase and a Phosphatase: Investigations of the Activation Step in Bacillus cereus Phosphopentomutase.

Iverson, T.M.Panosian, T.D.Birmingham, W.R.Nannemann, D.P.Bachmann, B.O.

(2012) Biochemistry 51: 1964-1975

  • DOI: 10.1021/bi201761h
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • Prokaryotic phosphopentomutases (PPMs) are di-Mn(2+) enzymes that catalyze the interconversion of α-D-ribose 5-phosphate and α-D-ribose 1-phosphate at an active site located between two independently folded domains. These prokaryotic PPMs belong to t ...

    Prokaryotic phosphopentomutases (PPMs) are di-Mn(2+) enzymes that catalyze the interconversion of α-D-ribose 5-phosphate and α-D-ribose 1-phosphate at an active site located between two independently folded domains. These prokaryotic PPMs belong to the alkaline phosphatase superfamily, but previous studies of Bacillus cereus PPM suggested adaptations of the conserved alkaline phosphatase catalytic cycle. Notably, B. cereus PPM engages substrates when the active site nucleophile, Thr-85, is phosphorylated. Further, the phosphoenzyme is stable throughout purification and crystallization. In contrast, alkaline phosphatase engages substrates when the active site nucleophile is dephosphorylated, and the phosphoenzyme reaction intermediate is only stably trapped in a catalytically compromised enzyme. Studies were undertaken to understand the divergence of these mechanisms. Crystallographic and biochemical investigations of the PPM(T85E) phosphomimetic variant and the neutral corollary PPM(T85Q) determined that the side chain of Lys-240 underwent a change in conformation in response to active site charge, which modestly influenced the affinity for the small molecule activator α-D-glucose 1,6-bisphosphate. More strikingly, the structure of unphosphorylated B. cereus PPM revealed a dramatic change in the interdomain angle and a new hydrogen bonding interaction between the side chain of Asp-156 and the active site nucleophile, Thr-85. This hydrogen bonding interaction is predicted to align and activate Thr-85 for nucleophilic addition to α-D-glucose 1,6-bisphosphate, favoring the observed equilibrium phosphorylated state. Indeed, phosphorylation of Thr-85 is severely impaired in the PPM(D156A) variant even under stringent activation conditions. These results permit a proposal for activation of PPM and explain some of the essential features that distinguish between the catalytic cycles of PPM and alkaline phosphatase.


    Organizational Affiliation

    Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States. tina.iverson@vanderbilt.edu



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PhosphopentomutaseA399Bacillus cereusMutation(s): 0 
Gene Names: deoBBC_4087
EC: 5.4.2.7
Find proteins for Q818Z9 (Bacillus cereus (strain ATCC 14579 / DSM 31 / JCM 2152 / NBRC 15305 / NCIMB 9373 / NRRL B-3711))
Explore Q818Z9 
Go to UniProtKB:  Q818Z9
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN
Query on MN

Download CCD File 
A
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.26 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.192 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 60.975α = 90
b = 75.706β = 90
c = 95.562γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHASERphasing
REFMACrefinement
CNSrefinement
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-02-29
    Type: Initial release
  • Version 1.1: 2012-03-21
    Changes: Database references