Delta atracotoxin produces potentially fatal neurotoxic symptoms in primates by slowing he inactivation of voltage-gated sodium channels [1]. The structure of atracotoxin comprises a core beta region containing a triple-stranded a thumb-like extension protruding from the beta region and a C-terminal helix. The beta region contains a cystine knot motif, a feature seen in other neurotoxic polypeptides [1].

1: The structure of versutoxin (delta-atracotoxin-Hv1) provides insights into the binding of site 3 neurotoxins to the voltage-gated sodium channel. Fletcher JI, Chapman BE, Mackay JP, Howden ME, King GF; Structure 1997;5:1525-1535. PMID:9384567