cgna is a member of a family of sea-anemone sodium-channel type 1 toxins. cgna shares structural similarities and sequence homology with other anemone type 1 toxins such as apa, apb and atx, and with the type 2 sodium channel toxin sh1 of "stichodactyla helianthus". the most distinctive feature in the primary structure between cgna and its related proteins lies in its difference in the distribution of electrostatic charge; cgna contains more negatively charged residues and a lower percentage of exposed hydrophobic residues than is typical for type i and ii toxins. this is likely to effect the binding of the toxin to sodium channels.