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Domain organization in Clostridium butulinum neurotoxin type E is unique: Its implication in faster translocationDomain organization in Clostridium butulinum neurotoxin type E is unique: Its implication in faster translocation
Structural highlights
FunctionBXE_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 catalyzes the hydrolysis of the 180-Arg-|-Ile-181 bond in SNAP-25. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedClostridium botulinum produces seven antigenically distinct neurotoxins [C. botulinum neurotoxins (BoNTs) A-G] sharing a significant sequence homology. Based on sequence and functional similarity, it was believed that their three-dimensional structures will also be similar. Indeed, the crystal structures of BoNTs A and B exhibit similar fold and domain association where the translocation domain is flanked on either side by binding and catalytic domains. Here, we report the crystal structure of BoNT E holotoxin and show that the domain association is different and unique, although the individual domains are similar to those of BoNTs A and B. In BoNT E, both the binding domain and the catalytic domain are on the same side of the translocation domain, and all three have mutual interfaces. This unique association may have an effect on the rate of translocation, with the molecule strategically positioned in the vesicle for quick entry into cytosol. Botulism, the disease caused by BoNT E, sets in faster than any other serotype because of its speedy internalization and translocation, and the present structure offers a credible explanation. We propose that the translocation domain in other BoNTs follows a two-step process to attain translocation-competent conformation as in BoNT E. We also suggest that this translocation-competent conformation in BoNT E is a probable reason for its faster toxic rate compared to BoNT A. However, this needs further experimental elucidation. Domain organization in Clostridium botulinum neurotoxin type E is unique: its implication in faster translocation.,Kumaran D, Eswaramoorthy S, Furey W, Navaza J, Sax M, Swaminathan S J Mol Biol. 2009 Feb 13;386(1):233-45. Epub 2008 Dec 24. PMID:19118561[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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