Chemoenzymatic synthesis of glycopolypeptides carrying alpha-Neu5Ac-(2-->3)-beta-D-Gal-(1-->3)-alpha-D-GalNAc, beta-D-Gal-(1-->3)-alpha-D-GalNAc, and related compounds and analysis of their specific interactions with lectins.

摘要: Glycopolypeptide (1) carrying the beta-D-Gal-(1-->3)-alpha-D-GalNAc unit as a kind model of asialo-type mucin was synthesized through three steps: enzymatic synthesis p-nitrophenyl disaccharide glycoside, reduction group, and coupling amino group with carboxyl poly(L-glutamic acid)s (PGA). In similar manner, glycopolypeptides (2-7) beta-D-Gal-(1-->3)-beta-D-GalNAc, beta-D-Gal-(1-->3)-beta-D-GlcNAc, beta-D-Gal-(1-->6)-alpha-D-GalNAc, beta-D-Gal-(1-->6)-beta-D-GalNAc, alpha-D-GalNAc, beta-D-GalNAc, respectively, were analogous polymers polymer 1. Glycopolypeptides 8 9 mimic sialo-type further prepared from 1 2 acceptor CMP-Neu5Ac by alpha2,3-(O)-sialyltransferase, respectively. Interactions these lectins investigated double-diffusion test hemagglutination-inhibition assay in terms an optical biosensor based on surface plasmon resonance. Polymers reacted strongly peanut (Arachis hypogaea) agglutinin (PNA) Agaricus bisporus (ABA). On other hand, sialylation ABA, but did not PNA. Other 3-7 show any reactivity for both lectins. These results that PNA acts precisely exo manner beta-D-Gal-(1-->3)-D-GalNAc sequence, while ABA endo manner. 6 7 substituted GalNAc soybean (Glycine max) Vicia villosa B4, regardless configuration glycosidic linkage. The interaction all Bauhinia purpurea much stronger than corresponding sugars. wheat germ (Triticum vulgaris) (WGA), to which Neu5Ac residues are needed binding, not. sugar-substituted interacted specifically Furthermore, 4-7 WGA, sugars It suggests N-acetyl along PGA backbone has cluster effect WGA. artificial shown be useful tools probes carbohydrate recognition modeling analysis glycoprotein-lectin interactions.