Crystal structure of the gal10 fusion protein galactose mutarotase/UDP-galactose 4-epimerase from Saccharomyces cerevisiae complexed with NAD, UDP-glucose, and galactose

Experimental Data Snapshot

  • Resolution: 1.85 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.196 

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The molecular architecture of galactose mutarotase/UDP-galactose 4-epimerase from Saccharomyces cerevisiae.

Thoden, J.B.Holden, H.M.

(2005) J Biol Chem 280: 21900-21907

  • DOI: https://doi.org/10.1074/jbc.M502411200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The metabolic pathway by which beta-D-galactose is converted to glucose 1-phosphate is known as the Leloir pathway and consists of four enzymes. In most organisms, these enzymes appear to exist as soluble entities in the cytoplasm. In yeast such as Saccharomyces cerevisiae, however, the first and last enzymes of the pathway, galactose mutarotase and UDP-galactose 4-epimerase, are contained within a single polypeptide chain referred to as Gal10p. Here we report the three-dimensional structure of Gal10p in complex with NAD(+), UDP-glucose, and beta-D-galactose determined to 1.85-A resolution. The enzyme is dimeric with dimensions of approximately 91 A x 135 A x 108 A and assumes an almost V-shaped appearance. The overall architecture of the individual subunits can be described in terms of two separate N- and C-terminal domains connected by a Type II turn formed by Leu-357 to Val-360. The first 356 residues of Gal10p fold into the classical bilobal topology observed for all other UDP-galactose 4-epimerases studied thus far. This N-terminal domain contains the binding sites for NAD(+) and UDP-glucose. The polypeptide chain extending from Glu-361 to Ser-699 adopts a beta-sandwich motif and harbors the binding site for beta-D-galactose. The two active sites of Gal10p are separated by over 50 A. This investigation represents the first structural analysis of a dual function enzyme in the Leloir pathway.

  • Organizational Affiliation

    Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
GAL10 bifunctional protein699Saccharomyces cerevisiaeMutation(s): 1 
Gene Names: GAL10
EC: (PDB Primary Data), (PDB Primary Data)
Find proteins for P04397 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Explore P04397 
Go to UniProtKB:  P04397
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP04397
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.85 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.196 
  • Space Group: I 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 120.9α = 90
b = 125.2β = 90
c = 142.3γ = 90
Software Package:
Software NamePurpose
PROTEUM PLUSdata collection
SAINTdata reduction
PROTEUM PLUSdata reduction
SAINTdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-04-05
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2012-05-02
    Changes: Structure summary
  • Version 1.4: 2013-05-08
    Changes: Non-polymer description
  • Version 1.5: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Derived calculations, Structure summary
  • Version 1.6: 2021-10-20
    Changes: Database references, Structure summary
  • Version 1.7: 2023-08-23
    Changes: Data collection, Refinement description