ω-agatoxin-IVA

ω-agatoxin-IVA (ω-AGA IVA) is a peptide originally isolated from funnel web-spider venom Agelenopsis aperta. This peptide is a specific blocker of P/Q-type calcium channel (Cav2.1) . It has been reported that ω-agatoxin IVA is a potent blocker of voltage-gated calcium channels in insect and vertebrate central neurons. The binding site for ω-agatoxin IVA has been localized in part to the extracellular S3–S4 loop in repeat IV of the α-1A Ca2+ channels, which is proximal to the S4 sensor domain. This is coherent with its functional effect (no pore-blocking activity, but gating modifier by a shift of channel activation towards more depolarized potentials) . This makes this toxin a voltage-dependent blocker of P/Q calcium channels.