Mass spectrometric investigations on Conus peptides

Molecular masses and primary structure determination of Conus peptides, such as alpha-, mu- and omega-conotoxins, conantokins and conopressins, were accurately measured by state-of-the-art mass spectrometric techniques using only 1-2 pmole quantities. Soft ionization of Conus peptides under electrospray, matrix-assisted laser desorption and continuous flow frit-FAB conditions produced their corresponding singly and multiply charged molecular ions which can be detected by mass spectrometric analysis. The molecular masses of Conus peptides were obtained by the deconvolution of the multiply charged pseudo-molecular ions. Mixture analysis without chromatographic separation can be accomplished by this approach. The ions formed during collision-induced dissociation of either singly or multiply charged ions of any reduced and derivatized peptide provided the corresponding sequences of the amino acids. Preliminary investigations indicate that the developed techniques and procedures could be applied in order to characterize the peptides present in unknown Conus venoms from the Bay of Bengal region.