Evidence is presented that the specificity of jacalin, the seed lectin from jack fruit (Artocarpus integrifolia), is not directed exclusively against the T-antigen disaccharide Galβ1,3GalNAc, lactose and galactose, but also against mannose and oligomannosides. Biochemical analyses based on surface-plasmon-resonance measurements, combined with the X-ray-crystallographic determination of the structure of a jacalin—α-methyl-mannose complex at 2Å resolution, demonstrated clearly that jacalin is fully capable of binding mannose. Besides mannose, jacalin also interacts readily with glucose, N-acetylneuraminic acid and N-acetylmuramic acid. Structural analyses demonstrated that the relatively large size of the carbohydrate-binding site enables jacalin to accommodate monosaccharides with different hydroxyl conformations and provided unambiguous evidence that the β-prism structure of jacalin is a sufficiently flexible structural scaffold to confer different carbohydrate-binding specificities to a single lectin.
Structural basis for the unusual carbohydrate-binding specificity of jacalin towards galactose and mannose
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Yves BOURNE, Corinne Houlès ASTOUL, Véronique ZAMBONI, Willy J. PEUMANS, Laurence MENU-BOUAOUICHE, Els J.M. Van DAMME, Annick BARRE, Pierre ROUGÉ; Structural basis for the unusual carbohydrate-binding specificity of jacalin towards galactose and mannose. Biochem J 15 May 2002; 364 (1): 173–180. doi: https://doi.org/10.1042/bj3640173
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