The structures of the H-C fragment of tetanus toxin with carbohydrate subunit complexes provide insight into ganglioside binding

The entry of tetanus neurotoxin into neuronal cells proceeds through the in itial binding of the toxin to gangliosides on the cell surface. The carboxy l-terminal fragment of the heavy chain of tetanus neurotoxin contains the g anglioside-binding site, which has not yet been fully characterized. The cr ystal structures of native H-C and of H-C soaked with carbohydrates reveal a number of binding sites and protide insight into the possible mode of gan glioside binding.