The Crystal Structure of UDP-GalNAc: polypeptide alpha-N-acetylgalactosaminyltransferase-T1

Experimental Data Snapshot

  • Resolution: 2.50 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.218 

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This is version 2.0 of the entry. See complete history


The beginnings of mucin biosynthesis: The crystal structure of UDP-GalNAc:polypeptide {alpha}-N-acetylgalactosaminyltransferase-T1

Fritz, T.A.Hurley, J.H.Trinh, L.B.Shiloach, J.Tabak, L.A.

(2004) Proc Natl Acad Sci U S A 101: 15307-15312

  • DOI: https://doi.org/10.1073/pnas.0405657101
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    UDP-GalNAc:polypeptide alpha-N-acetylgalactosaminyltransferases (ppGaNTases) initiate the formation of mucin-type, O-linked glycans by catalyzing the transfer of alpha-N-acetylgalactosamine from UDP-GalNAc to Ser or Thr residues of core proteins to form the Tn antigen (GalNAc-alpha-1-O-Ser/Thr). ppGaNTases are unique among glycosyltransferases in containing a C-terminal lectin domain. We present the x-ray crystal structure of a ppGaNTase, murine ppGaNTase-T1, and show that it folds to form distinct catalytic and lectin domains. The association of the two domains forms a large cleft in the surface of the enzyme that contains a Mn2+ ion complexed by invariant D209 and H211 of the "DXH" motif and by invariant H344. Each of the three potential lectin domain carbohydrate-binding sites (alpha, beta, and gamma) is located on the active-site face of the enzyme, suggesting a mechanism by which the transferase may accommodate multiple conformations of glycosylated acceptor substrates. A model of a mucin 1 glycopeptide substrate bound to the enzyme shows that the spatial separation between the lectin alpha site and a modeled active site UDP-GalNAc is consistent with the in vitro pattern of glycosylation observed for this peptide catalyzed by ppGaNTase-T1. The structure also provides a template for the larger ppGaNTase family, and homology models of several ppGaNTase isoforms predict dramatically different surface chemistries consistent with isoform-selective acceptor substrate recognition.

  • Organizational Affiliation

    Section on Biological Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Polypeptide N-acetylgalactosaminyltransferase 1472Mus musculusMutation(s): 0 
Gene Names: Galnt1
Find proteins for O08912 (Mus musculus)
Explore O08912 
Go to UniProtKB:  O08912
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO08912
Sequence Annotations
  • Reference Sequence


Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
Glycosylation Resources
GlyTouCan:  G15407YE
GlyCosmos:  G15407YE
GlyGen:  G15407YE
Experimental Data & Validation

Experimental Data

  • Resolution: 2.50 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.218 
  • Space Group: P 43
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 65.605α = 90
b = 65.605β = 90
c = 125.947γ = 90
Software Package:
Software NamePurpose
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-10-26
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary