title: Carbohydrate-dependent binding of the cell-free hemagglutinin of Vibrio cholerae to glycoprotein and glycolipid.
abstract: The carbohydrate-binding specificity of the cell-free hemagglutinin (HA) of Vibrio cholerae (K.K. Banerjee, A.N. Ghose, K. Datta-Roy, S.C. Pal, and A.C. Ghose, Infect. Immun.58:3698-3705, 1990) was studied by using glycoconjugates with defined sugar sequences. The HA was not inhibited by simple sugars including glucobiose, galabiose, and their N-acetylated derivatives. The hemagglutination of rabbit erythrocytes by the HA was inhibited moderately by fetuin, calf thyroglobulin, and human alpha 1-acid glycoprotein, all of which contain multiple asparagine-linked complex-type oligosaccharide units alone or in combination with serine/threonine-linked oligosaccharide units. The inhibitory potencies of the glycoproteins increased approximately 10-fold following removal of the terminal sialic acid and were completely destroyed by exhausative proteolysis. The HA agglutinated phosphatidylcholine liposomes containing GM1-ganglioside or its asialo-derivative in the presence of Ca2+ ions. The association constants of the complexes of the HA with asialofetuin, asialothyroglobulin, GM1-ganglioside, and asialo-GM1-ganglioside were determined by an enzyme-linked immunosorbent assay-based assay and found to be 1.7 x 10(7) M-1, 1.5 x 10(7) M-1, 1.8 x 10(7) M-1, and 2.4 x 10(7) M-1, respectively. Studies using chemically modified glycoproteins and plant lectins with defined sugar specificity revealed that the HA recognized the terminal beta 1-galactosyl moiety of these glycoconjugates. There was no evidence for the presence of an extended carbohydrate-binding domain in the HA molecule or a preference of the HA for a complex, branched oligosaccharide structure. Similar to the mechanisms proposed for the binding of cholera toxin and Shiga toxin to glycolipids and neoglycoproteins, the strong interaction of V. cholerae cell-free HA with glycoconjugates appeared to be a consequence of multiple weak binding to terminal beta1-galactosyl moieties of the glycoproteins or glycolipids.
authors.affiliation: Division of Immunology and Vaccine Development, National Institute of Cholera and Enteric Diseases, Calcutta, India.
authors.forename: N
authors.initials: N
authors.lastname: Saha
authors.forename: K K
authors.initials: KK
authors.lastname: Banerjee
mesh_terms: D000818:Animals; D001212:Asialoglycoproteins / Q000378:metabolism; D050260:Carbohydrate Metabolism; D002240:Carbohydrate Sequence; D060748:Fetuins; D005677:G(M1) Ganglioside / Q000378:metabolism; D006017:Glycolipids / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006385:Hemagglutination Inhibition Tests; D006388:Hemagglutinins / Q000378:metabolism*; D007106:Immune Sera / Q000276:immunology; D008297:Male; D008969:Molecular Sequence Data; D011817:Rabbits; D000509:alpha-Fetoproteins / Q000378:metabolism
chemical_list: D001212:Asialoglycoproteins; D060748:Fetuins; D006017:Glycolipids; D006023:Glycoproteins; D006388:Hemagglutinins; D007106:Immune Sera; D000509:alpha-Fetoproteins; C017029:asialofetuin; D005677:G(M1) Ganglioside; C018835:asialo GM1 ganglioside