Association of botulinum neurotoxins with synaptic vesicle protein complexes.
Botulinum neurotoxins (BoNTs) elicit flaccid paralysis by cleaving SNARE proteins within peripheral neurons. BoNTs are classified into seven serotypes, termed A-G, based on antibody cross-neutralization. Clostridia produce BoNTs as single-chain toxins that are cleaved into a di-chain protein that comprises an N-terminal zinc metalloprotease domain that is linked by a disulfide bond to the C-terminal translocation/receptor-binding domain. BoNT/A and BoNT/B utilize synaptic vesicle protein 2 (SV2) and synaptotagmin, respectively, as receptors for entry into neurons. Using affinity chromatography, BoNT/A and BoNT/B were found to bind a synaptic vesicle protein complex in CHAPS extracts of synaptic vesicles. Mass spectroscopy identified synaptic vesicle protein 2, synaptotagmin I, synaptophysin, vesicle-associated membrane protein 2, and the vacuolar ATPase-proton pump as components of the BoNT-synaptic vesicle protein complex. BoNT/A and BoNT/B possessed unique density-gradient profiles when bound to synaptic vesicle protein complexes. The identification of BoNT/A and BoNT/B bound to synaptic vesicle protein complexes provides insight into the interactions of BoNT and neuronal receptors.
Department of Microbiology and Molecular Genetics, 8701 Watertown Plank Rd., Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Michael R
MR
Baldwin
Joseph T
JT
Barbieri
D000818:Animals; D001905:Botulinum Toxins / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000378:metabolism*; D009498:Neurotoxins / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding; D050600:SNARE Proteins / Q000187:drug effects / Q000378:metabolism; D013329:Structure-Activity Relationship; D013572:Synaptic Vesicles / Q000187:drug effects / Q000378:metabolism*
D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D009498:Neurotoxins; D050600:SNARE Proteins; D001905:Botulinum Toxins