Which of the following glycolipids serves as a receptor for cholera toxin?
Specificity cholera toxin exemplifies glycan protein recognition medical consequence and cell biology tool. Vibrio cholerae AB5 holotoxin comprises catalytic A1 subunit ADP ribosyltransferase and homopentameric B subunits each containing binding pocket pentasaccharide GM1 Gal beta1-3 GalNAc beta1-4 Neu5Ac alpha2-3 Gal beta1-4 Glc ceramide. Key hydrogen bonds terminal galactose sialic acid provide nanomolar affinity positioning toxin on lipid rafts enterocytes small intestine. Raft mediated endocytosis delivers toxin retrograde trans Golgi ER where A1 ADP ribosylates Gs alpha arginine two hundr
Ref: Merritt et al., Protein Science 1994, Cholera toxin B subunit GM1 complex structure and pathogenesis.