Characterization of voltage-dependent calcium channel blocking peptides from the venom of the tarantula Grammostola rosea

► Three Ca channel blocking peptides were identified from the venom of the tarantula. ► The peptide GTx1-15 is novel and inhibits T-type calcium channel (Cav3.1). ► GTx1-15 shows highest sequence homology with sodium channel blocker peptides. ► Surface atmospheres were similar in the low-voltage-activated ion channel blockers.