1A78

COMPLEX OF TOAD OVARY GALECTIN WITH THIO-DIGALACTOSE

Summary for 1A78

• Entry DOI: 10.2210/pdb1a78/pdb
• Related PRD ID: PRD_900027
• Descriptor: GALECTIN-1, beta-D-galactopyranose-(1-1)-1-thio-beta-D-galactopyranose, 2,3-DIHYDROXY-1,4-DITHIOBUTANE, ... (4 entities in total)
• Functional Keywords: s-lectin, carbohydrate binding, complex (lectin-saccharide), lectin
• Biological source: Bufo arenarum
• Total number of polymer chains: 2
• Total formula weight: 30322.37

Authors

Amzel, L.M.,Bianchet, M.A.,Ahmed, H.,Vasta, G.R. (deposition date: 1998-03-20, release date: 1998-10-14, Last modification date: 2024-05-22)

Primary citation

Bianchet, M.A.,Ahmed, H.,Vasta, G.,Amzel, L.M.
Soluble beta-galactosyl-binding lectin (galectin) from toad ovary: crystallographic studies of two protein-sugar complexes
Proteins, 40:378-388, 2000

PubMed Abstract: Galectin-1, S-type beta-galactosyl-binding lectins present in vertebrate and invertebrate species, are dimeric proteins that participate in cellular adhesion, activation, growth regulation, and apoptosis. Two high-resolution crystal structures of B. arenarum galectin-1 in complex with two related carbohydrates, LacNAc and TDG, show that the topologically equivalent hydroxyl groups in the two disaccharides exhibit identical patterns of interaction with the protein. Groups that are not equivalent between the two sugars present in the second moiety of the disaccharide, interact differently with the protein, but use the same number and quality of interactions. The structures show additional protein-carbohydrate interactions not present in previously reported lectin-lactose complexes. These contacts provide an explanation for the enhanced affinity of galectin-1 for TDG and LacNAc relative to lactose. Galectins are in dimer-monomer equilibrium at physiological protein concentrations, suggesting that this equilibrium may be involved in organ-specific regulation of activity. Comparison of B. arenarum with other galectin-1 structures shows that among different galectins there are significant changes in accessible surface area buried upon dimer formation, providing a rationale for the variations observed in the free-energies of dimerization. The structure of the B. arenarum galectin-1 has a large cleft with a strong negative potential that connects the two binding sites at the surface of the protein. Such a striking characteristic suggests that this cleft is probably involved in interactions of the galectin with other intra or extra-cellular proteins. Proteins 2000;40:378-388.

PubMed: 10861929
DOI: 10.1002/1097-0134(20000815)40:3<378::AID-PROT40>3.0.CO;2-7

Experimental method

X-RAY DIFFRACTION (2 Å)