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From Proteopedia
Cryo-EM structure of Botulinum neurotoxin serotype B
Structural highlights
Function[BXB_CLOBO] Botulinum toxin acts by inhibiting neurotransmitter release. It binds to peripheral neuronal synapses, is internalized and moves by retrograde transport up the axon into the spinal cord where it can move between postsynaptic and presynaptic neurons. It inhibits neurotransmitter release by acting as a zinc endopeptidase that cleaves the '76-Gln-|-Phe-77' bond of synaptobrevin-2. Publication Abstract from PubMedBotulinum 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 A 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. Structural Analysis of Botulinum Neurotoxins Type B and E by Cryo-EM.,Kosenina S, Martinez-Carranza M, Davies JR, Masuyer G, Stenmark P Toxins (Basel). 2021 Dec 23;14(1). pii: toxins14010014. doi:, 10.3390/toxins14010014. PMID:35050991[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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