Fig. 6. Pairwise comparison of identity between Cn11 and the other 10 representative groups of scorpion toxin specific for Na⁺ channels. The amino acid sequence of the 10 representative examples of each sub-group of Na⁺ channel scorpion toxin was compared with the amino acid sequence of Cn11 (the eleventh group proposed here). AaHII is toxin II from Androctonus australis Hector, the prototype of an -scorpion toxin; CssII is toxin II from Centruroides sufussus sufussus, the prototype of a ß-scorpion toxin; Tsgamma is toxin gamma from Tityus serrulatus; LqhIT2 is insect toxin 2 from Leiurus quinquestriatus hebraeus; LqqIV is toxin IV from Leiurus quinquestriatus quinquestriatus; LqqIII is toxin III from the same scorpion; AaHIT4, toxin 4, is an insect toxin from Androctonus australis Hector; CsEv3 is variant 3 from Centruroides sculpturatus Ewing; Cn10, toxin 10, is an insect toxin from Centruroides noxius Hoffmann; AaHIT is an insect toxin from Androctonus australis Hector; and Cn11 is from this study (data from Possani et al., 1999a, 2000, 2001). Gaps (dashes) were introduced to enhance similarities. Cysteine residues are in bold type. The right-hand column indicates the percentage identity of the pairwise comparison.