title: The biological activity of botulinum neurotoxin type C is dependent upon novel types of ganglioside binding sites.
abstract: The seven botulinum neurotoxins (BoNT) cause muscle paralysis by selectively cleaving core components of the vesicular fusion machinery. Their extraordinary activity primarily relies on highly specific entry into neurons. Data on BoNT/A, B, E, F and G suggest that entry follows a dual receptor interaction with complex gangliosides via an established ganglioside binding region and a synaptic vesicle protein. Here, we report high resolution crystal structures of the BoNT/C cell binding fragment alone and in complex with sialic acid. The WY-motif characteristic of the established ganglioside binding region was located on an exposed loop. Sialic acid was co-ordinated at a novel position neighbouring the binding pocket for synaptotagmin in BoNT/B and G and the sialic acid binding site in BoNT/D and TeNT respectively. Employing synaptosomes and immobilized gangliosides binding studies with BoNT/C mutants showed that the ganglioside binding WY-loop, the newly identified sialic acid-co-ordinating pocket and the area corresponding to the established ganglioside binding region of other BoNTs are involved in ganglioside interaction. Phrenic nerve hemidiaphragm activity tests employing ganglioside deficient mice furthermore evidenced that the biological activity of BoNT/C depends on ganglioside interaction with at least two binding sites. These data suggest a unique cell binding and entry mechanism for BoNT/C among clostridial neurotoxins.
authors.affiliation: Institut für Toxikologie, OE 5340 Institut für Biochemie, OE 4310, Medizinische Hochschule Hannover, Carl-Neuberg-Str 1, 30625 Hannover, Germany.
authors.forename: Jasmin
authors.initials: J
authors.lastname: Strotmeier
authors.forename: Shenyan
authors.initials: S
authors.lastname: Gu
authors.forename: Stephan
authors.initials: S
authors.lastname: Jutzi
authors.forename: Stefan
authors.initials: S
authors.lastname: Mahrhold
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.forename: Andreas
authors.initials: A
authors.lastname: Pich
authors.forename: Timo
authors.initials: T
authors.lastname: Eichner
authors.forename: Hans
authors.initials: H
authors.lastname: Bigalke
authors.forename: Andreas
authors.initials: A
authors.lastname: Rummel
authors.forename: Rongsheng
authors.initials: R
authors.lastname: Jin
authors.forename: Thomas
authors.initials: T
authors.lastname: Binz
mesh_terms: D000818:Animals; D001665:Binding Sites; D001905:Botulinum Toxins / Q000737:chemistry* / Q000378:metabolism* / Q000633:toxicity; D018360:Crystallography, X-Ray; D003964:Diaphragm / Q000502:physiology; D051379:Mice; D008958:Models, Molecular; D019158:N-Acetylneuraminic Acid / Q000737:chemistry* / Q000378:metabolism*; D010791:Phrenic Nerve / Q000187:drug effects; D011485:Protein Binding; D017434:Protein Structure, Tertiary
chemical_list: D001905:Botulinum Toxins; C096324:botulinum toxin type C; D019158:N-Acetylneuraminic Acid