Expressed by the venom duct. Both hydroxylated and non-hydroxylated forms are mostly and only present in part 2 (proximal of the venom bulb) of the venom duct, respectively. The cysteine framework is III (CC-C-C-CC). Classified in the M-2 branch, since 2 residues stand between the fourth and the fifth cysteine residues. Contains 3 disulfide bonds. Belongs to the conotoxin M superfamily.