Expressed by the venom duct. All three forms are mostly present in part 5 of venom duct (distal part near the pharynx) and less abundantly present in part 4. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. The cysteine framework is VI/VII (C-C-CC-C-C). Contains 3 disulfide bonds. Exists in 5 different forms, depending on bromination and hydroxylation. Form P2 does not contain brominated tryptophan (PubMed:23031820), form P2-WBr has one brominated tryptophan at position 60 (PubMed:22709442, PubMed:23031820), form P2-2WBr has two brominated tryptophans at position 59 and 60 (PubMed:23031820), form hydroxyPro-P2-WBr has a hydroxyproline at position 49 and a brominated tryptophan at position 59 (PubMed:22709442), and form hydroxyPro-P2-2WBr has an hydroxyproline at position 49 and two brominated tryptophan at position 59 and 60 (PubMed:22709442). Belongs to the conotoxin O2 superfamily.