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Aleuria aurantia lectin (AAL) is a fungal protein that specifically recognised fucose moiety in glycans. The crystal structure of AAL complexed with fucose has been solved at 1.5 A resolution. AAL displays a dimer composition, each subunit consists of a six-bladed beta-propeller fold and of a small antiparallel two-strands beta-sheet that play a role in dimerization. Primary sequence of AAL contains six internal repeats [1] corresponded to particular blades, crystal structure reveals five fucose molecules per AAL monomer in binding sites formed by two adjacent blades. Surface plasmon resonance experiments have been performed on a series of fucose containing oligosaccharides to determine equilibrium dissociation constants for lectine-oligosaccharide interaction. Measurements confirm the broad specificity of the lectin, with a slight preference for alpha-Fuc1-2Gal disaccharide. AAL shows high sequence similarity with a lectin from plant pathogenic bacterium Ralstonia solanacearum (RSL) [2]. As RSL is smaller (91 amino acid residues compared to 312 of AAL), only two typical internal repeats can be found in sequence. SPR studies demonstrated that RSL shares similar specificity as AAL but highly prefers alpha-Fuc1-2 linkage. [1] Fukumori, F., Takeuchi, N., Hagiwara, T., Ohbayashi, H., Endo, T., Kochibe, N., Nagata, Y., and Kobata, A J. Biochem. 107, 190-196 (1990) [2] Sudakevitz, D., Imberty, A., and Gilboa-Garber, N., J. Biochem. 132, 353-358 (2002)
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