The surface electrostatic potential of GM1 indicates a non-polar, membrane-embedded part corresponding to ceramide (white areas), and an acidic part protruding in the extracellular space corresponding to the sialic-acid-containing saccharide part (red areas). (a) CLQ bound to the tip of the carbohydrate moiety of GM1. (b) Molecular mechanism of CLQ–ganglioside interactions. (c) Molecular dynamics simulations revealed a second site of interaction.