Strategies toward structural and functional ‘optimization’ of animal peptide toxins

Background: venoms of a variety of animal species (i.e. scorpions, snakes, spiders, sea anemones, marine cone snails, worms, and insects) are rich sources of bioactive compounds that possess obvious pharmacological, therapeutic and/or biotechnological values. A majority of these compounds are peptides that mainly target enzymes, membrane receptors or ion channels. Aim: In recent years, much efforts of researchers have been focused on characterizing and ‘improving’ the pharmacological profile of some venom toxins, mainly because of their structural/functional diversity and potential value as chemotherapeutic drugs in the treatment of specific human pathologies. Materials and methods: This study reviews the strategies towards optimization of animal peptide toxins. Results: These peptides are most often in a size range that allows their production in vitro by chemical synthesis or genetic engineering. Unfortunately, they rarely display the required characteristics in terms of selectivity, affinity, stability and targeting with regard to the desired application. During the last decade, a number of successful structural approaches or strategies have been developed to improve the intrinsic potential of venom peptides. Using different strategies (reviewed herein), a number of highly potent and selective toxin-derived candidate drugs were designed and produced by chemical synthesis. Conclusion: Such strategies proved to be effective as several toxin-based drugs are already marketed while an increasing number of candidate chemotherapeutics are currently being developed in clinical phase.