6g5k
Crystal structure of the binding domain of Botulinum Neurotoxin type B in complex with human synaptotagmin 1Crystal structure of the binding domain of Botulinum Neurotoxin type B in complex with human synaptotagmin 1
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. [SYT1_HUMAN] May have a regulatory role in the membrane interactions during trafficking of synaptic vesicles at the active zone of the synapse. It binds acidic phospholipids with a specificity that requires the presence of both an acidic head group and a diacyl backbone. A Ca(2+)-dependent interaction between synaptotagmin and putative receptors for activated protein kinase C has also been reported. It can bind to at least three additional proteins in a Ca(2+)-independent manner; these are neurexins, syntaxin and AP2. Publication Abstract from PubMedAlthough botulinum neurotoxin serotype A (BoNT/A) products are common treatments for various disorders, there is only one commercial BoNT/B product, whose low potency, likely stemming from low affinity toward its human receptor synaptotagmin 2 (hSyt2), has limited its therapeutic usefulness. We express and characterize two full-length recombinant BoNT/B1 proteins containing designed mutations E1191M/S1199Y (rBoNT/B1MY) and E1191Q/S1199W (rBoNT/B1QW) that enhance binding to hSyt2. In preclinical models including human-induced pluripotent stem cell neurons and a humanized transgenic mouse, this increased hSyt2 affinity results in high potency, comparable to that of BoNT/A. Last, we solve the cocrystal structure of rBoNT/B1MY in complex with peptides of hSyt2 and its homolog hSyt1. We demonstrate that neuronal surface receptor binding limits the clinical efficacy of unmodified BoNT/B and that modified BoNT/B proteins have promising clinical potential. Engineered botulinum neurotoxin B with improved binding to human receptors has enhanced efficacy in preclinical models.,Elliott M, Favre-Guilmard C, Liu SM, Maignel J, Masuyer G, Beard M, Boone C, Carre D, Kalinichev M, Lezmi S, Mir I, Nicoleau C, Palan S, Perier C, Raban E, Zhang S, Dong M, Stenmark P, Krupp J Sci Adv. 2019 Jan 16;5(1):eaau7196. doi: 10.1126/sciadv.aau7196. eCollection 2019, Jan. PMID:30746458[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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