Structural basis of functional mimicry between carbohydrate and peptide ligands of Con A

Crystallographic studies have shown independent binding sites for sugar and peptide ligands of concanavalin A, although they were considered functional mimics based on biochemical experiments. The topological correlation of la-residue peptide with different carbohydrate ligands of concanavalin A showed similarity between trimannose and the YPY region of the peptide establishing structural mimicry. Molecular docking of trimannose and the YPY motif on the reciprocal binding sites revealed equivalent interactions and energetics implying that the peptide-binding sites may constitute additional sugar-binding subsites of concanavalin A. The binding of a mannose-rich neoglycoprotein with significantly higher affinity compared with that of the methyl alpha-D-mannopyranoside is consistent with this interpretation. (C) 2000 Academic Press.