Conus Peptides: Phylogenetic Range of Biological Activity.

The major function of the venoms of the predatory marine snails belonging to the genus Conus is to paralyze prey. Thus, the venom of each Conus species acts on receptors and ion channels of the prey; previous studies suggested much less activity on homologous receptor targets in more distant taxa. In this article, we address the question of whether some peptide components of Conus venoms ("conopeptides") have "cross-phylum" biological activity. We examined the venom of Conus textile, a mollusk-hunting Conus, using a mammalian biological activity assay. We purified a 23 amino acid "convulsant peptide" with potent activity in the mammalian CNS, even though it comes from the venom of a snail-hunting Conus species. A survey of Conus textile venom fractions indicates that, in addition to the convulsant peptide, many other components of this venom will exhibit "cross-phylum" biological activity. Conopeptides with broad-range phylogenetic specificity should be useful tools for studying the evolution of receptors and ion channels, and of nervous systems.