The carbohydrate-binding specificity of lectins from the
seeds of Canavalia maritima and Dioclea
grandiflora was studied by hapten-inhibition of
haemagglutination using various sugars and sugar derivatives
as inhibitors, including N-acetylneuraminic acid and
N-acetylmuramic acid. Despite some discrepancies, both
lectins exhibited a very similar carbohydrate-binding
specificity as previously reported for other lectins from
Diocleinae (tribe Phaseoleae, sub-tribe
Diocleinae). Accordingly, both lectins exhibited almost
identical hydropathic profiles and their three-dimensional
models built up from the atomic coordinates of ConA looked
very similar. However, docking experiments of glucose and
mannose in their monosaccharide-binding sites, by comparison
with the ConA-mannose complex used as a model, revealed
conformational changes in side chains of the amino acid
residues involved in the binding of monosaccharides. These
results fully agree with crystallographic data showing that
binding of specific ligands to ConA requires conformational
chances of its monosaccharide-binding site.