Omega-conotoxins act at presynaptic membranes, they bind and block voltage-gated calcium channels (Cav). Specifically acts on L-type channels. It blocks molluscan dihydropyridine-sensitive calcium channels. Expressed by the venom duct. 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). Belongs to the conotoxin O1 superfamily.