Botulinum neurotoxin type A receptor-binding domain (BoNT/A H_C)

The **Botulinum neurotoxin type A receptor-binding domain** (BoNT/A H_C) is the C-terminal segment of the heavy chain (residues ~873–1297) of the botulinum neurotoxin produced by *Clostridium botulinum*. This domain is responsible for high-affinity binding to neuronal cell surfaces via dual recognition of protein (primarily SV2) and polysialoganglioside (notably GT1b and GD1a) receptors, initiating internalization of the holotoxin and subsequent paralysis. Structural studies reveal a two-part domain (N-terminal jelly roll and C-terminal β-trefoil fold) that forms conserved epitopes critical for binding. These surface epitopes are targets for neutralizing antibodies and peptide inhibitors as potential countermeasures and for vaccine development. The BoNT/A binding domain is a validated therapeutic target for antitoxin drugs and is a primary determinant of the neurotoxicity and cell specificity of the entire toxin molecule[1][2][3][4][6][7].

Other names

Botulinum neurotoxin type A binding domainBoNT/A H_CBoNT/A receptor-binding domainHeavy chain C-terminal domain of botulinum neurotoxin type A

Antagonism of receptor binding (by antibodies or peptide inhibitors)