Figure 1.

Sequence comparison of select 4/7 framework α-Ctxs. Conotoxins are classified into various subclasses based on the number of cysteine residues present in the sequence and the number of amino acid residues between them (63). Peptides of the α-Ctx subclass contain two disulfide-connected pairs of cysteines. Thus, for example, α-Ctxs with four residues between Cys² and Cys³ and seven between Cys⁸ and Cys¹⁶ belong to the 4/7 framework subclass. Residues in black are variable, and those in red are conserved among this α-Ctx set. The disulfide bonds between Cys residues are depicted with lines. *, C-terminal amidation.