Voltage-gated sodium channels are targets for toxins from the venom of the spider Heriaeus melloteei

Abstract

Three novel peptides were isolated from the venom of the spider Heriaeus melloteei (Thomisidae) and characterized. The peptides named Hm-1, 2 and 3 blocked voltage-gated Na+ channels at concentrations in the order of 100 nM. Activity of the purified peptides was investigated in Na+ channel isoforms of mammals and insects. Hm-1 and 2 appeared to act as pore blockers, whereas Hm-3 modulated the channel activation process. The toxins described exhibit minor similarity with other known peptides and may therefore constitute new groups of Na+ channel ligands.