ABSTRACT
The conformational stability of a typical small conotoxin peptide is achieved by intramolecular disulfide crosslinking between paired cysteine residues. Cone snails are among the most diverse groups of predators in tropical marine reefs. Since conotoxins are directly encoded by nucleic acid templates, Cone snails also provide an opportunity to study toxin genomes of great complexity. The biochemical characterization of venom components has focused on the biologically active peptides. Since many active conotoxins are amidated at their carboxy termini, it has been suspected that at least some conotoxins are derived from larger propeptide molecules. Analysis of cDNA clones for King Kong propeptides provided additional data to support the folding hypothesis. The identification of cDNA clones for a family of toxins from Conus textile has identified the propeptide precursors to mature conotoxin molecules. It should be possible to identify amino acid sequences which may signal this post-translational modification.
