2ZML

Crystal structure of basic winged bean lectin in complex with Gal-ALPHA 1,4 Gal

Summary for 2ZML

• Entry DOI: 10.2210/pdb2zml/pdb
• Related: 1WBL 2DU0 2E53 2ZMK 2ZMN
• Descriptor: Basic agglutinin, alpha-D-galactopyranose-(1-4)-alpha-D-galactopyranose, alpha-L-fucopyranose-(1-3)-[2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)]2-acetamido-2-deoxy-beta-D-glucopyranose, ... (8 entities in total)
• Functional Keywords: legume lectin, sugar specificity, winged bean lectin, sugar binding protein
• Biological source: Psophocarpus tetragonolobus (Goa bean)
• Total number of polymer chains: 4
• Total formula weight: 110514.27

Authors

Kulkarni, K.A.,Katiyar, S.,Surolia, A.,Vijayan, M.,Suguna, K. (deposition date: 2008-04-19, release date: 2008-07-29, Last modification date: 2024-11-20)

Primary citation

Kulkarni, K.A.,Katiyar, S.,Surolia, A.,Vijayan, M.,Suguna, K.
Structure and sugar-specificity of basic winged-bean lectin: structures of new disaccharide complexes and a comparative study with other known disaccharide complexes of the lectin.
Acta Crystallogr.,Sect.D, 64:730-737, 2008

PubMed Abstract: Crystal structures of the complexes of basic winged-bean agglutinin with the disaccharides Galalpha1-4Gal (galabiose), Galalpha1-6Glc (mellibiose) and Galalpha1-4Galbeta-Et have been determined and the complex with Galalpha1-2Gal has been modelled. The interactions of the nonreducing Gal with the lectin at the primary site are the same as those in the known complexes with disaccharides having the alpha1-->3 linkage. The second residue in Galalpha1-4Gal and Galalpha1-6Glc forms a water bridge to the lectin, while the ethyl group in Galalpha1-4Galbeta-Et makes nonpolar interactions. In complexes involving disaccharides with alpha1-3 linkages, which form part of the A and B blood-group substances, the second sugar residue forms a direct hydrogen bond to the variable loop in the binding site of the lectin. This in part explains the specificity of the lectin for the blood-group substances and also the higher affinity of alpha1-->3-linked disaccharides for the lectin compared with disaccharides involving other linkages. Including those reported here, 14 crystal structures involving the lectin, accounting for 54 crystallographically independent subunits, are available. A comparative study of these structures shows that the region involving the curved beta-sheet which nestles the metal ions is relatively rigid. The carbohydrate-binding region is perched on this region. The flat beta-sheet, which is involved in oligomerization and exhibits considerable variability in legume lectins, is relatively flexible. Indeed, the structures of basic winged-bean lectin have been of critical importance in establishing legume lectins as a family of proteins in which small alterations in essentially the same tertiary structure lead to large variations in quaternary association. They have also provided a structural explanation of the blood-group specificity of the lectin.

PubMed: 18566508
DOI: 10.1107/S0907444908011323

Experimental method

X-RAY DIFFRACTION (2.65 Å)