Structure-function relationship of monocot mannose-binding lectins.

The monocot mannose-binding lectins are an extended superfamily of structurally and evolutionarily related proteins, which until now have been isolated from species of the Amaryllidaceae, Alliaceae, Araceae, Orchidaceae, and Liliaceae. To explain the obvious differences in biological activities, the structure-function relationships of the monocot mannose-binding lectins were studied by a combination of glycan-binding studies and molecular modeling using the deduced amino acid sequences of the currently known lectins. Molecular modeling indicated that the number of active mannose-binding sites per monomer varies between three and zero. Since the number of binding sites is fairly well correlated with the binding activity measured by surface plasmon resonance, and is also in good agreement with the results of previous studies of the biological activities of the mannose-binding lectins, molecular modeling is of great value for predicting which lectins are best suited for a particular application.