FULL CHARACTERIZATION OF CONUS VENOM BY CHROMATOGRAPHY AND MASS SPECTROMETRY

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Conotoxins are the bio-active components of Conus snail venom. Conus snails are a large genus of venomous gastropods comprising approximately 500 species. All conus snail species are predators that inject venom to capture or kill prey. The species are subdivided in fish eaters (piscivorous), mollusc eaters (molluscivorous) and worm eaters (vermivorous). Interestingly, Conus venoms have a remarkable diversity of biological active neuropeptides. Their targets are ion channels and receptors in the neuromuscular system. For instance, the venom of Conus Geographus contains high affinity peptides (conotoxins) that act on voltage sensitive calcium channels, sodium channels and N-methyl-D-aspartate (NMDA) receptors. Although conotoxins have been studied for over 30 years, only a few components of the venoms of some species have been identified on the protein level. One of the aims of this project is to map the enormous complexity of the venom derived from both Conus Ventricosus and Conus Textile. We will utilize mass spectrometry for protein and peptide assignment. Peptides with biological functions often contain disulfide bridges (cystines) connecting two cysteine residues via their free thiol groups. Disulfide bond formation is one of the most common posttranslational modification. Disulfides are important to maintain or establish the 3D structure of proteins and peptides and are also involved in regulating peptide activity. An example of highly disulfide bridged peptides are conotoxins. Typically these toxins are 20 to 30 amino acids long containing 2 or 3 disulfides. A secondairy aim of this project is the assignment of disulfides in conotoxins. Chromatography and mass spectrometry can be used to first purify and isolate conotoxins from Conus venom and map the cysteine scaffold and determine the cystine connectivity utilizing tandem mass spectrometry.