1H9P

Crystal Structure of Dioclea guianensis Seed Lectin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.289 
  • R-Value Work: 0.239 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal Structure of Native and Cd/Cd-Substituted Dioclea Guianensis Seed Lectin. A Novel Manganese-Binding Site and Structural Basis of Dimer-Tetramer Association

Wah, D.A.Romero, A.Gallego, F.Cavada, B.S.Ramos, M.V.Grangeiro, T.B.Sampaio, A.H.Calvete, J.J.

(2001) J.Mol.Biol. 310: 885

  • DOI: 10.1006/jmbi.2001.4814
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Diocleinae legume lectins are a group of oligomeric proteins whose subunits display a high degree of primary structure and tertiary fold conservation but exhibit considerable diversity in their oligomerisation modes. To elucidate the structural deter ...

    Diocleinae legume lectins are a group of oligomeric proteins whose subunits display a high degree of primary structure and tertiary fold conservation but exhibit considerable diversity in their oligomerisation modes. To elucidate the structural determinants underlaying Diocleinae lectin oligomerisation, we have determined the crystal structures of native and cadmium-substituted Dioclea guianensis (Dguia) seed lectin. These structures have been solved by molecular replacement using concanavalin (ConA) coordinates as the starting model, and refined against data to 2.0 A resolution. In the native (Mn/Ca-Dguia) crystal form (P4(3)2(1)2), the asymmetric unit contains two monomers arranged into a canonical legume lectin dimer, and the tetramer is formed with a symmetry-related dimer. In the Cd/Cd-substituted form (I4(1)22), the asymmetric unit is occupied by a monomer. In both crystal forms, the tetrameric association is achieved by the corresponding symmetry operators. Like other legume lectins, native D. guianensis lectin contains manganese and calcium ions bound in the vicinity of the saccharide-combining site. The architecture of these metal-binding sites (S1 and S2) changed only slightly in the cadmium/cadmium-substituted form. A highly ordered calcium (native lectin) or cadmium (Cd/Cd-substituted lectin) ion is coordinated at the interface between dimers that are not tetrameric partners in a similar manner as the previously identified Cd(2+) in site S3 of a Cd/Ca-ConA. An additional Mn(2+) coordination site (called S5), whose presence has not been reported in crystal structures of any other homologous lectin, is present in both, the Mn/Ca and the Cd/Cd-substituted D. guianensis lectin forms. On the other hand, comparison of the primary and quaternary crystal structures of seed lectins from D. guianensis and Dioclea grandiflora (1DGL) indicates that the loop comprising residues 117-123 is ordered to make interdimer contacts in the D. grandiflora lectin structure, while this loop is disordered in the D. guianensis lectin structure. A single amino acid difference at position 131 (histidine in D. grandiflora and asparagine in D. guianensis) drastically reduces interdimer contacts, accounting for the disordered loop. Further, this amino acid change yields a conformation that may explain why a pH-dependent dimer-tetramer equilibrium exists for the D. guianensis lectin but not for the D. grandiflora lectin.


    Related Citations: 
    • Molecular Characterization and Crystallization of Diocleinae Lectins
      Calvete, J.J.,Thole, H.H.,Raida, M.,Urbanke, C.,Romero, A.,Grangeiro, T.B.,Ramos, M.V.,Almeida, I.M.,Guimaraes, F.N.,Cavada, B.S.
      (1999) Biochim.Biophys.Acta 1430: 367


    Organizational Affiliation

    Centro de Investigaciones Biológicas, C.S.I.C., Madrid, Spain.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
LECTIN ALPHA CHAIN
A
237Dioclea guianensisMutation(s): 0 
Find proteins for P81637 (Dioclea guianensis)
Go to UniProtKB:  P81637
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN
Query on MN

Download SDF File 
Download CCD File 
A
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
CD
Query on CD

Download SDF File 
Download CCD File 
A
CADMIUM ION
Cd
WLZRMCYVCSSEQC-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.289 
  • R-Value Work: 0.239 
  • Space Group: I 41 2 2
Unit Cell:
Length (Å)Angle (°)
a = 90.314α = 90.00
b = 90.314β = 90.00
c = 108.276γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
MOSFLMdata reduction
SCALAdata scaling
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-03-23
    Type: Initial release
  • Version 1.1: 2014-02-05
    Type: Atomic model, Derived calculations, Non-polymer description, Other, Refinement description, Source and taxonomy, Structure summary, Version format compliance