Experimental Data Snapshot

  • Resolution: 2.50 Å
  • R-Value Free: 0.289 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.228 

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Isolectins I-A and I-B of Griffonia (Bandeiraea) Simplicifolia. Crystal Structure of Metal-Free Gs I-B(4) and Molecular Basis for Metal Binding and Monosaccharide Specificity.

Lescar, J.Loris, R.Mitchell, E.Gautier, C.Chazalet, V.Cox, V.Wyns, L.Perez, S.Breton, C.Imberty, A.

(2002) J Biol Chem 277: 6608

  • DOI: https://doi.org/10.1074/jbc.M109867200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Seeds from the African legume shrub Griffonia simplicifolia contain several lectins. Among them the tetrameric lectin GS I-B(4) has strict specificity for terminal alpha Gal residues, whereas the closely related lectin GS I-A(4) can also bind to alpha GalNAc. These two lectins are commonly used as markers in histology or for research in xenotransplantation. To elucidate the basis for the fine difference in specificity, the amino acid sequences of both lectins have been determined and show 89% identity. The crystal structure of GS I-B(4), determined at 2.5-A resolution, reveals a new quaternary structure that has never been observed in other legume lectins. An unexpected loss of both Ca(2+) and Mn(2+) ions, which are necessary for carbohydrate binding in legume lectins, may be related to a particular amino acid sequence Pro-Glu-Pro in the metal binding loop. Comparison with demetallized concanavalin A reveals a different process for the loss of metal ions and for the subsequent loss of carbohydrate binding activity. The GS I-A x alpha GalNAc and GS I-B x alpha Gal complexes were constructed using homology modeling and docking approaches. The unusual presence of an aromatic amino acid at position 47 (Tyr in I-A and Trp in I-B) explains the strong preference for alpha-anomeric sugars in both isolectins. Alteration at one amino acid position, Ala(106) in I-A versus Glu(106) in I-B, is the basis for the observed specificities toward alpha GalNAc and alpha Gal.

  • Organizational Affiliation

    Centre de Recherches sur les Macromolécules Végétales, CNRS, Université Joseph Fourier, BP 53, F-38041 Grenoble cedex 09, France.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
GSI-B4 ISOLECTIN257Griffonia simplicifoliaMutation(s): 0 
Find proteins for Q8W1R6 (Griffonia simplicifolia)
Explore Q8W1R6 
Go to UniProtKB:  Q8W1R6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8W1R6
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.50 Å
  • R-Value Free: 0.289 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.228 
  • Space Group: P 64 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 75.927α = 90
b = 75.927β = 90
c = 190.566γ = 120
Software Package:
Software NamePurpose
HKLdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-11-29
    Type: Initial release
  • Version 1.1: 2011-09-07
    Changes: Atomic model, Data collection, Database references, Derived calculations, Non-polymer description, Other, Refinement description, Structure summary, Version format compliance
  • Version 1.2: 2019-12-18
    Changes: Derived calculations, Other
  • Version 1.3: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Derived calculations, Structure summary
  • Version 1.4: 2023-12-13
    Changes: Data collection, Database references, Refinement description, Structure summary