Identification of a new specific Kv1.3 channel blocker, Ctri9577, from the scorpion Chaerilus tricostatus

► The first neurotoxin of Chaerilidae family was identified by cDNA method. ► The new toxin peptide, Ctri9577, was a new member of α-KTx15 subfamily. ► The recombinant Ctri9577 peptide selectively inhibited Kv1.3 channel current. ► Ctri9577 might have a unique interaction feature targeting Kv1.3 channel.