Complex binding site lectins

The ability of PO to interact with the acetyl residues of chitin allows us to compare them with monovalent lectins (i.e. extensins) which when binding with hemicellulose are only affected in a medium with a high ionic strength (Brownleader et al., 2006). As a rule, POs are bound with the plant cell wall and act as its modifiers. Some POs can form complexes with an extensin of cell walls (Brownleader et al., 2006). Consequently, chitin-specific sites that are capable of interacting with polysaccharides exist in the molecules of PO, and these sites can resemble the membrane receptor binding sites or else be similar to the domains of heparinbinding proteins (Kim et al., 2001). 

The carbohydrate-binding sites of WGA are probably situated at the surface of the protein molecule. The pH dependences of association constants for lectin-chitotriose binding indicate that an ionizable group, pK = 3.9, is probably involved in complex-formation.494,504 This observation is especially noteworthy, inasmuch as protein carboxyl... 

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