Molecular recognition XII. The binding of the H human blood group determinants and congeners by a lectin of Galactiatenuiflora

Abstract

70. 151 1 (1992).The H-type 2 human blood group-related trisaccharide (a-L-Fuc-(lcj2b)-P-D-Gal-(] b4a)-P-D-GlcNAc-OMe (52)) IS bound by the anti-H lectin of Galnctin tenuiflora very differently than by the lectin I of Ulex europaeus. The reason why the Galactia lectin binds the H-type 1 related trisaccharide (a-~-Fuc-(lc~2b)-~-~-Gal-(lb3a)-~-~-GlcNAc-OMe (5)) more strongly and methyl a-L-fucopyranoside much more weakly than does the U1e.r lectin is that, for the Galactia lectin, 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 Ulex lectin. The H-type 2 (52). Galactia lectin 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 CH'O-la, NHAc-2a, and CH,OH-6a groups likely remain in the aqueous phase remote from the surface of the protein.REMY CROMER, ULRIKE SPOHR, DEVESHWARI P. KHARE, JAQUES LEPENDU et RAYMOND U. LEMIEUX. Can. J. Chem. 70, 1511 (1992).On observe que la liaison entre le trisaccharide du groupe sanguin H-de type 2 (a-~-F~c-(Ic--t2b)-P-~-Gal-(lb+4a)-P-D-GlcNAc-OMe (52)) et la lectine anti-H de Galactia tenuiflora est trks differente de celle qui le lie 2 la lectine I de (5)) qui est plus forte -et la liaison avec l'a-L-fucopyranoside de mtthyle qui est beaucoup plus faible -que celles avec la lectine d'Ulex est que, pour la lectine de Galactia, les groupes hydroxyles aux positions 3a, 3b, 4b et 4c sont indispensables pour la formation de complexe alors que ce sont les groupes hydroxyles en positions 3b, 2c, 3c et 4c qui fournissent les interactions polaires cles dans le cas de la lectine d'Ule-r. Le complexe groupe H de type 2 (52). la lectine de Galactin semble possCder des groupes hydroxyles dans les positions 6b, 2c et 3c au niveau de, ou k la proximite de, la ptriphCrie du site de liaison alors que les trois groupes hydroxyles clCs sont lies par des ponts hydrogenes avec la prottine qui se trouve 2 l'interieur du site de liaison, protege de I'eau. 1'Ulex eziropaeus. La raison de la liaison entre la lectine de Galactia et le trisaccharide relie groupe H de type 1 (a-L- Fuc-(lc+2b)-P-~-Gal-(lb3a)-P-~-GlcNA~-OMeLes groupes CH,O-en la, NHAc-en 2a et Ch,OH-en 6a restent vraisemblablement dans la phase aqueuse qui se trouve CloignCe de la surface de la proteine.[Traduit par la rCdaction]

Molecular recognition XIII. The binding of the H-type 2 human blood group determinant by a winged bean (Psophocarpus tetragonolobus) acidic lectin

“…On the basis of this information the changes in the thermodynamic parameters caused by various structural modifications are examined in terms of the observed enthalpy*ntropy compensations. As was found in several other cases (5)(6)(7), the surface of 1 that is recognized by WBA I1 is relatively small and polyamphiphilic.…”

“…The radioimmunoassays were performed according to a published procedure ( I 3). The plastic tubes were coated using a solution of WBA-I1 (100 pg/mL) in 0.1 N phos- Except for the mono-0-methyl derivatives of 1 that are presented in Table 1, the syntheses of the various other congeners used in this study have already been reported (6,7,14). The mono-0-methyl derivatives were prepared following procedures similar to those used for the synthesis of 0-methyl derivatives of the Lewis b tetrasaccharide (4).…”

“…Indeed, it was subsequently shown (3) that the affinity for 2'-fucosyllactose (a-L-Fuc-(1 + 2)-P-D-Gal-(1 + 4)qP-DGlc) is 13 times greater than that for the H-disaccharide (a-L-'For the previous publication in this series, see ref. 7 .…”

Inhibitors of endo-α-mannosidase. Part II. 1-Deoxy-3-O-(α-D-glucopyranosyl)-mannojirimycin and congeners modified in the mannojirimycin unit

“…The disaccharide 1-deoxy-3-0-(a-D-glucopyranosy1)-mannojirimycin (9) has been shown to strongly inhibit the action of endo-a-D-mannosidase ( l ) , a glycoprotein-processing hydrolase that releases aDGlc(l+ 3 )~M a n from incompletely deglucosylated GlcMan,GlcNAc, oligosaccharide of immature N-linked glycoproteins (2,3). Although deoxymannojirimycin itself is known to be a strong exomannosidase inhibitor (4), it was found inactive towards endo-mannosidase (3).…”

“…It is to be noted in this regard that extensive protein-oligosaccharide binding studies have been performed with numerous lectins (5)(6)(7)(8)(9). monoclonal antibodies (10)(11)(12).…”