A combined molecular modelling and CIDNP study of similarities in the pattern of ligand binding in mammalian and avian galectins

Galectins (Galactose binding lectins) from bacteria, plants and animals have been shown to possess tyrosine or tryptophan residues that form hydrophobic contacts with their ligands in the binding sites. At the present time, the X-ray structures of only two galectins from human and bovine tissues are known. In the present study we applied X-ray data of bovine heart galectin-1 as a template for homology modelling of a number of galectins from mammalian and avian tissues. The conservation of one tryptophan and at least one histidine in binding pocket can be observed from the comparison of the model structures. We also show that it is possible to obtain information of the architecture of the binding pocket of several galectins in solution using CIDNP (Chemically Induced Dynamic Nuclear Polarisation) techniques. The CIDNP approach offers a possibility to analyse these lectins in solution thereby providing supplementary information to the available X-ray data. All studied galectins show comparable alterations when they are recorded by CIDNP-technique in the absence and in the presence of their specific carbohydrate ligands.