1AFB

STRUCTURAL BASIS OF GALACTOSE RECOGNITION IN C-TYPE ANIMAL LECTINS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.217 

wwPDB Validation   3D Report Full Report


Ligand Structure Quality Assessment 

Created with Raphaël 2.3.0Worse 01 BetterLigand structure goodness of fit to experimental dataBest fitted NGAClick on this verticalbar to view details

This is version 1.5 of the entry. See complete history


Literature

Structural basis of galactose recognition by C-type animal lectins.

Kolatkar, A.R.Weis, W.I.

(1996) J Biol Chem 271: 6679-6685

  • Primary Citation of Related Structures:  
    1AFA, 1AFB, 1AFD

  • PubMed Abstract: 

    The asialoglycoprotein receptors and many other C-type (Ca2+-dependent) animal lectins specifically recognize galactose- or N-acetylgalactosamine-terminated oligosaccharides. Analogous binding specificity can be engineered into the homologous rat mannose-binding protein A by changing three amino acids and inserting a glycine-rich loop (Iobst, S. T., and Drickamer, K. (1994) J. Biol. Chem. 269, 15512-15519). Crystal structures of this mutant complexed with beta-methyl galactoside and N-acetylgalactosamine (GalNAc) reveal that as with wild-type mannose-binding proteins, the 3- and 4-OH groups of the sugar directly coordinate Ca2+ and form hydrogen bonds with amino acids that also serve as Ca2+ ligands. The different stereochemistry of the 3- and 4-OH groups in mannose and galactose, combined with a fixed Ca2+ coordination geometry, leads to different pyranose ring locations in the two cases. The glycine-rich loop provides selectivity against mannose by holding a critical tryptophan in a position optimal for packing with the apolar face of galactose but incompatible with mannose binding. The 2-acetamido substituent of GalNAc is in the vicinity of amino acid positions identified by site-directed mutagenesis (Iobst, S. T., and Drickamer, K. (1996) J. Biol. Chem. 271, 6686-6693) as being important for the formation of a GalNAc-selective binding site.


  • Organizational Affiliation

    Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
MANNOSE-BINDING PROTEIN-AA [auth 1],
B [auth 2],
C [auth 3]
154Rattus norvegicusMutation(s): 5 
UniProt
Find proteins for P19999 (Rattus norvegicus)
Explore P19999 
Go to UniProtKB:  P19999
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP19999
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
NGA
Query on NGA

Download Ideal Coordinates CCD File 
D [auth 1],
I [auth 2],
M [auth 3]
2-acetamido-2-deoxy-beta-D-galactopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-JAJWTYFOSA-N
CA
Query on CA

Download Ideal Coordinates CCD File 
E [auth 1]
F [auth 1]
G [auth 1]
J [auth 2]
K [auth 2]
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
CL
Query on CL

Download Ideal Coordinates CCD File 
H [auth 1],
Q [auth 3]
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.217 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 80.8α = 90
b = 84.5β = 104.3
c = 97.1γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 

Created with Raphaël 2.3.0Worse 01 BetterLigand structure goodness of fit to experimental dataBest fitted NGAClick on this verticalbar to view details

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1996-04-03
    Type: Initial release
  • Version 1.1: 2008-03-03
    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: Data collection, Database references, Derived calculations, Structure summary
  • Version 1.4: 2021-11-03
    Changes: Database references, Structure summary
  • Version 1.5: 2024-11-20
    Changes: Data collection, Structure summary