Structural Analysis of Botulinum Neurotoxins Type B and E by Cryo-EM.
Kosenina, S., Martinez-Carranza, M., Davies, J.R., Masuyer, G., Stenmark, P.(2021) Toxins (Basel) 14
- PubMed: 35050991 
- DOI: https://doi.org/10.3390/toxins14010014
- Primary Citation of Related Structures:  
7QFP, 7QFQ - PubMed Abstract: 
Botulinum neurotoxins (BoNTs) are the causative agents of a potentially lethal paralytic disease targeting cholinergic nerve terminals. Multiple BoNT serotypes exist, with types A, B and E being the main cause of human botulism. Their extreme toxicity has been exploited for cosmetic and therapeutic uses to treat a wide range of neuromuscular disorders. Although naturally occurring BoNT types share a common end effect, their activity varies significantly based on the neuronal cell-surface receptors and intracellular SNARE substrates they target. These properties are the result of structural variations that have traditionally been studied using biophysical methods such as X-ray crystallography. Here, we determined the first structures of botulinum neurotoxins using single-particle cryogenic electron microscopy. The maps obtained at 3.6 and 3.7 Å for BoNT/B and /E, respectively, highlight the subtle structural dynamism between domains, and of the binding domain in particular. This study demonstrates how the recent advances made in the field of single-particle electron microscopy can be applied to bacterial toxins of clinical relevance and the botulinum neurotoxin family in particular.
Organizational Affiliation: 
Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.