Saccharide Orientation at the Cell Surface Affects Glycolipid Receptor Function

• Published in: Proceedings of the National Academy of Sciences - PNAS 1991-10, Vol.88 (20), p.9340-9344
• Main Authors: Stromberg, Nicklas, Nyholm, Per-Georg, Pascher, Irmin, Normark, Staffan
• Format: Article
• Language: English
• Subjects: Adhesins, Escherichia coli; Agglutination; Animals; Bacteria; Bacterial Adhesion; Bacterial Outer Membrane Proteins - genetics; Bacterial Outer Membrane Proteins - metabolism; Bacteriology; Biological and medical sciences; Carbohydrate Conformation; Carbohydrate Sequence; Cell lines; Epitopes; Erythrocyte membrane; Erythrocytes; Erythrocytes - physiology; Escherichia coli - genetics; Escherichia coli - physiology; Fundamental and applied biological sciences. Psychology; Genetic Variation; Glycolipids; Glycolipids - blood; glycosphingolipids; Hemagglutination; Humans; Microbiology; Models, Molecular; Molecular Sequence Data; P branes; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Receptors; Receptors, Mitogen - physiology; saccharides
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.88.20.9340

Three allelic variants of P-pilus-associated G-adhesins (lectins) with different cell-binding properties were recently described. Here we have analyzed Escherichia coli HB101 strains expressing the recombinant G-adhesin variants for their ability to agglutinate erythrocytes from various species as this relates to the glycosphingolipid (GSL) composition in the erythrocyte membranes. All three variants exhibit similar specificities for the globo-series GSLs affixed to artificial surfaces. However, only the PapGJ96adhesin induces agglutination of erythrocytes having globotriaosylceramide (GbO3) [Gal(α1-4)LacCer] as the major GSL. Furthermore, only PapGAD110induces strong agglutination of erythrocytes having globotetraosylceramide (GbO4) [GalNAc(β1-3)Gal(α1-4)LacCer] as the major GSL, while PrsGJ96alone agglutinates those containing globopentaosylceramide (GbO5) [GalNAc(α1-3)GalNAc(β1-3)Gal(α1-4)LacCer]. Molecular modeling of these globo-GSLs demonstrates different saccharide orientations to the membrane surface for these isoreceptors. We suggest that the differential binding of the three G-adhesin variants results from differences in epitope presentation at the membrane among these globo-GSLs.