Gamma-conotoxins may act on voltage-gated non-specific cation pacemaker channels (HCN). Expressed by the venom duct. The cysteine framework is VI/VII (C-C-CC-C-C). The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Three forms of this peptides have been described. The unmodified Am6.1a (Am3286) is not detected in the venom; Am6.1b (Am3408) is only Trp brominated, while Am6.1c (Am3452) is both Trp brominated and Glu gamma-carboxyglutamated. Both Am6.1b and Am6.1c are detected in the venom. Belongs to the conotoxin O2 family.