| Abstrakt: |
The H-type 2 human blood group-related trisaccharide (α-L-Fuc-(1c → 2b)-β-D-Gal-(1b → 4a)-β-D-GlcNAc-OMe (52)) is bound by the anti-H lectin of Galactiatenuifloravery differently than by the lectin I of Ulexeuropaeus. The reason why the Galactialectin binds the H-type 1 related trisaccharide (α-L-Fuc-(1c → 2b)-β-D-Gal-(1b → 3a)-β-D-GlcNAc-OMe (5)) more strongly and methyl α-L-fucopyranoside much more weakly than does the Ulexlectin is that, for the Galactialectin, the hydroxyl groups at positions 3a, 3b, 4b, and 4c are indispensable to complex formation whereas it is the hydroxyl groups at positions 3b, 2c, 3c, and 4c which provide the key polar intractions in the case of the Ulexlectin. The H-type 2 (52)•Galactialectin complex appears to have the hydroxyl groups at positions 6b, 2c, and 3c at or near the periphery of the combining site and the three key hydroxyl groups hydrogen bonded to the protein deep within the combining site and sheltered from water. The CH3O-1a, NHAc-2a, and CH2OH-6a groups likely remain in the aqueous phase remote from the surface of the protein. |
