The structure of the tetanus toxin reveals pH ‐mediated domain dynamics

Abstract

The tetanus neurotoxin (Te NT ) is a highly potent toxin produced by Clostridium tetani that inhibits neurotransmission of inhibitory interneurons, causing spastic paralysis in the tetanus disease. Te NT differs from the other clostridial neurotoxins by its unique ability to target the central nervous system by retrograde axonal transport. The crystal structure of the tetanus toxin reveals a “closed” domain arrangement stabilised by two disulphide bridges, and the molecular details of the toxin's interaction with its polysaccharide receptor. An integrative analysis combining X‐ray crystallography, solution scattering and single particle electron cryo‐microscopy reveals pH ‐mediated domain rearrangements that may give Te NT the ability to adapt to the multiple environments encountered during intoxication, and facilitate binding to distinct receptors. image Tetanus toxin is a deadly neurotoxin targeting the central nervous system. The structure of the holotoxin reveals pH ‐mediated domain rearrangements important for sorting, stability, receptor‐interactions and the response to the environments encountered during intoxication. The crystal structure of the tetanus holotoxin reveals a “closed” domain arrangement. Single particle cryo‐ EM presents a “semi‐open” domain organization. pH regulates the positions of the tetanus toxin's binding domain.