1G9F

CRYSTAL STRUCTURE OF THE SOYBEAN AGGLUTININ IN A COMPLEX WITH A BIANTENNARY BLOOD GROUP ANTIGEN ANALOG

Summary for 1G9F

• Entry DOI: 10.2210/pdb1g9f/pdb
• Related: 1SBD 1SBF 2SBA
• Descriptor: LECTIN, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, beta-D-galactopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-2)-[beta-D-galactopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-3)]beta-D-galactopyranose, ... (6 entities in total)
• Functional Keywords: jelly-roll fold, legume lectin, sugar binding protein
• Biological source: Glycine max (soybean)
• Total number of polymer chains: 1
• Total formula weight: 29026.06

Authors

Buts, L.,Hamelryck, T.W.,Dao-Thi, M.-H.,Loris, R.,Wyns, L.,Etzler, M.E. (deposition date: 2000-11-23, release date: 2001-06-13, Last modification date: 2024-10-16)

Primary citation

Buts, L.,Dao-Thi, M.H.,Loris, R.,Wyns, L.,Etzler, M.,Hamelryck, T.
Weak protein-protein interactions in lectins: the crystal structure of a vegetative lectin from the legume Dolichos biflorus.
J.Mol.Biol., 309:193-201, 2001

PubMed Abstract: The legume lectins are widely used as a model system for studying protein-carbohydrate and protein-protein interactions. They exhibit a fascinating quaternary structure variation, which becomes important when they interact with multivalent glycoconjugates, for instance those on cell surfaces. Recently, it has become clear that certain lectins form weakly associated oligomers. This phenomenon may play a role in the regulation of receptor crosslinking and subsequent signal transduction. The crystal structure of DB58, a dimeric lectin from the legume Dolichos biflorus reveals a separate dimer of a previously unobserved type, in addition to a tetramer consisting of two such dimers. This tetramer resembles that formed by DBL, the seed lectin from the same plant. A single amino acid substitution in DB58 affects the conformation and flexibility of a loop in the canonical dimer interface. This disrupts the formation of a stable DBL-like tetramer in solution, but does not prohibit its formation in suitable conditions, which greatly increases the possibilities for the cross-linking of multivalent ligands. The non-canonical DB58 dimer has a buried symmetrical alpha helix, which can be present in the crystal in either of two antiparallel orientations. Two existing structures and datasets for lectins with similar quaternary structures were reconsidered. A central alpha helix could be observed in the soybean lectin, but not in the leucoagglutinating lectin from Phaseolus vulgaris. The relative position and orientation of the carbohydrate-binding sites in the DB58 dimer may affect its ability to crosslink mulitivalent ligands, compared to the other legume lectin dimers.

PubMed: 11491289
DOI: 10.1006/jmbi.2001.4639

Experimental method

X-RAY DIFFRACTION (2.5 Å)