Crystal structures show that botulinum toxins bind simultaneously to two sites on neurons. This dual interaction allows them to use a Trojan-horse strategy to enter nerve terminals, with deadly effect. Botulinum neurotoxins (BoNTs) are some of the most deadly substances known to mankind. By blocking nerve function, they cause botulism, a severe condition that may ultimately lead to muscular and respiratory paralysis. These sophisticated bacterial proteins owe their toxicity to their extraordinary specificity for neurons and to their enzymatic activity. In this issue, papers by Jin et al. and Chai et al. describe the mechanisms by which BoNT/B — a toxin that causes human botulism — recognizes the surface of neuron junctions (synapses). This work provides insight into how other BoNTs may exert their lethal action, and describes a mode of binding that might be used by other biological compounds.
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