Structure of E. coli GlpX with its substrate fructose 1,6-bisphosphate

Experimental Data Snapshot

  • Resolution: 1.85 Å
  • R-Value Free: 0.216 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.177 

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Structural and Biochemical Characterization of the Type II Fructose-1,6-bisphosphatase GlpX from Escherichia coli.

Brown, G.Singer, A.Lunin, V.V.Proudfoot, M.Skarina, T.Flick, R.Kochinyan, S.Sanishvili, R.Joachimiak, A.Edwards, A.M.Savchenko, A.Yakunin, A.F.

(2009) J Biol Chem 284: 3784-3792

  • DOI: https://doi.org/10.1074/jbc.M808186200
  • Primary Citation of Related Structures:  
    1NI9, 3BIG, 3BIH, 3D1R

  • PubMed Abstract: 

    Gluconeogenesis is an important metabolic pathway, which produces glucose from noncarbohydrate precursors such as organic acids, fatty acids, amino acids, or glycerol. Fructose-1,6-bisphosphatase, a key enzyme of gluconeogenesis, is found in all organisms, and five different classes of these enzymes have been identified. Here we demonstrate that Escherichia coli has two class II fructose-1,6-bisphosphatases, GlpX and YggF, which show different catalytic properties. We present the first crystal structure of a class II fructose-1,6-bisphosphatase (GlpX) determined in a free state and in the complex with a substrate (fructose 1,6-bisphosphate) or inhibitor (phosphate). The crystal structure of the ligand-free GlpX revealed a compact, globular shape with two alpha/beta-sandwich domains. The core fold of GlpX is structurally similar to that of Li+-sensitive phosphatases implying that they have a common evolutionary origin and catalytic mechanism. The structure of the GlpX complex with fructose 1,6-bisphosphate revealed that the active site is located between two domains and accommodates several conserved residues coordinating two metal ions and the substrate. The third metal ion is bound to phosphate 6 of the substrate. Inorganic phosphate strongly inhibited activity of both GlpX and YggF, and the crystal structure of the GlpX complex with phosphate demonstrated that the inhibitor molecule binds to the active site. Alanine replacement mutagenesis of GlpX identified 12 conserved residues important for activity and suggested that Thr(90) is the primary catalytic residue. Our data provide insight into the molecular mechanisms of the substrate specificity and catalysis of GlpX and other class II fructose-1,6-bisphosphatases.

  • Organizational Affiliation

    Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario M5G 1L6, Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Fructose-1,6-bisphosphatase class II glpX337Escherichia coli K-12Mutation(s): 1 
Gene Names: glpXb3925JW3896
Find proteins for P0A9C9 (Escherichia coli (strain K12))
Explore P0A9C9 
Go to UniProtKB:  P0A9C9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A9C9
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.85 Å
  • R-Value Free: 0.216 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.177 
  • Space Group: P 4 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 91.296α = 90
b = 91.296β = 90
c = 84.913γ = 90
Software Package:
Software NamePurpose
CrystalCleardata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2008-12-23
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Database references, Derived calculations, Structure summary
  • Version 1.3: 2021-10-20
    Changes: Database references, Structure summary
  • Version 1.4: 2023-08-30
    Changes: Data collection, Refinement description