Pyrococcus furiosus galactokinase in complex with galactose, ADP and magnesium

Experimental Data Snapshot

  • Resolution: 2.90 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.230 
  • R-Value Observed: 0.232 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Substrate specificity and mechanism from the structure of Pyrococcus furiosus galactokinase

Hartley, A.Glynn, S.E.Barynin, V.Baker, P.J.Sedelnikova, S.E.Verhees, C.de Geus, D.van der Oost, J.Timson, D.J.Reece, R.J.Rice, D.W.

(2004) J Mol Biol 337: 387-398

  • DOI: https://doi.org/10.1016/j.jmb.2004.01.043
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Galactokinase (GalK) catalyses the first step of the Leloir pathway of galactose metabolism, the ATP-dependent phosphorylation of galactose to galactose-1-phosphate. In man, defects in galactose metabolism can result in disorders with severe clinical consequences, and deficiencies in galactokinase have been linked with the development of cataracts within the first few months of life. The crystal structure of GalK from Pyrococcus furiosus in complex with MgADP and galactose has been determined to 2.9 A resolution to provide insights into the substrate specificity and catalytic mechanism of the enzyme. The structure consists of two domains with the active site in a cleft at the domain interface. Inspection of the substrate binding pocket identifies the amino acid residues involved in galactose and nucleotide binding and points to both structural and mechanistic similarities with other enzymes of the GHMP kinase superfamily to which GalK belongs. Comparison of the sequence of the Gal3p inducer protein, which is related to GalK and which forms part of the transcriptional activation of the GAL gene cluster in the yeast Saccharomyces cerevisiae, has led to an understanding of the molecular basis of galactose and nucleotide recognition. Finally, the structure has enabled us to further our understanding on the functional consequences of mutations in human GalK which cause galactosemia.

  • Organizational Affiliation

    Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D, E
A, B, C, D, E, F, G, H, I
352Pyrococcus furiosusMutation(s): 4 
Gene Names: GALK
Find proteins for Q9HHB6 (Pyrococcus furiosus (strain ATCC 43587 / DSM 3638 / JCM 8422 / Vc1))
Explore Q9HHB6 
Go to UniProtKB:  Q9HHB6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9HHB6
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on ADP

Download Ideal Coordinates CCD File 
AA [auth F]
DA [auth G]
GA [auth H]
JA [auth I]
L [auth A]
AA [auth F],
DA [auth G],
GA [auth H],
JA [auth I],
L [auth A],
O [auth B],
R [auth C],
U [auth D],
X [auth E]
C10 H15 N5 O10 P2
Query on GLA

Download Ideal Coordinates CCD File 
BA [auth G]
EA [auth H]
HA [auth I]
J [auth A]
M [auth B]
BA [auth G],
EA [auth H],
HA [auth I],
J [auth A],
M [auth B],
P [auth C],
S [auth D],
V [auth E],
Y [auth F]
C6 H12 O6
Query on MG

Download Ideal Coordinates CCD File 
CA [auth G]
FA [auth H]
IA [auth I]
K [auth A]
N [auth B]
CA [auth G],
FA [auth H],
IA [auth I],
K [auth A],
N [auth B],
Q [auth C],
T [auth D],
W [auth E],
Z [auth F]
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
A, B, C, D, E
A, B, C, D, E, F, G, H, I
Experimental Data & Validation

Experimental Data

  • Resolution: 2.90 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.230 
  • R-Value Observed: 0.232 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 211.974α = 90
b = 355.672β = 90
c = 165.613γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALEPACKdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2004-04-06
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Data collection, Database references, Derived calculations, Structure summary
  • Version 1.4: 2024-04-03
    Changes: Data collection, Database references, Refinement description, Structure summary