|Detection of C. botulinum BoNT-E Heavy Chain by Western Blot. Western blot shows recombinant C. botulinum BoNT-E Heavy Chain (10 ng/lane). PVDF membrane was probed with 1 µg/mL of Sheep Anti-C. botulinum BoNT-E Heavy Chain Antigen Affinity-purified Polyclonal Antibody (Catalog # AF7135) followed by HRP-conjugated Anti-Sheep IgG Secondary Antibody (Catalog # HAF016). A specific band was detected for BoNT-E Heavy Chain at approximately 50 kDa (as indicated). This experiment was conducted under reducing conditions and using Immunoblot Buffer Group 8.|
BoNT/E HCR (Botulinum neurotoxin serotype E heavy chain receptor) is a 105 kDa component of BoNT/E, a member of the peptidase M27 family of molecules. BoNT/E is the product of Clostridium botulinum, and inhibits neurotransmitter release from neuromuscular junctions. This is accomplished by toxin internalization with subsequent cleavage of membrane-associated SNAP25, thus blocking synaptic vesicle fusion with the presynaptic membrane. The 155 kDa BoNT/E precursor is 1251 amino acids (aa) in length. Following internalization and precursor proteolytic cleavage by host proteases, it assumes a mature form that contains a 50 kDa disulfide-linked 422 aa light chain/enzyme N-terminus, and a 105 kDa, 829 aa heavy chain/receptor-binding C-terminus. The heavy chain has two components, a 327 aa translocation domain (aa 518-840), and a 408 aa cell membrane SV2:ganglioside binding region (aa 844-1250). The heavy chain creates a channel within the endosome that allows for redox rupture of the disulfide bond and entry of the light chain into the cytosol. The E heavy chain shares less that 50% aa identity with the BoNT/A heavy chain.