Animal venoms represent a vast library of bioactive peptides and proteins with proven potential not only as research tools but also as drug leads and therapeutics. This is illustrated elegantly in cone snails (genus Conus). Conus venom consists of a mixture of hundreds of peptides (conotoxins) with a diverse assortment of molecular targets including voltage- and ligand-gated ion channels, G-protein coupled receptors and neurotransmitter transporters. Several conotoxins have found use as important research tools while some are being used or developed as therapeutics. The primary objective of this study was the discovery of novel conotoxin sequences from the venom gland of Conus victoriae.
To this end, a combination of state-of-the-art techniques in molecular biology and bioinformatics was utilized; including cDNA library normalization, high-throughput 454 sequencing, de novo transcriptome assembly and annotation with BLAST and profile hidden Markov models. Subsequent matching of the transcriptome to a mass spectrometry profile of the crude venom was used to interrogate venom peptide composition and confirm post-translational modifications present in the mature venom peptides.
We report the discovery of over 100 unique conotoxin sequences from 20 gene superfamilies. Many of the sequences identified are new members of known conotoxin superfamilies, some will help to redefine these superfamilies and others represent altogether new classes of conotoxin. This work paints a comprehensive portrait of the molecular diversity present in Conus venom and demonstrates how an animal venom gland can be efficiently mined to generate a library of sequences encoding bioactive peptides.