Characterization of Venom from Conus obscurus in Search of Novel Peptide Sequences

Abstract

In this study, Conus obscurus milked venom has been analyzed in search of novel bioactive peptide sequences and fragments. About 250 diverse milked venoms were observed in high-performance liquid chromatography (HPLC) and pooled. A peptide survey and peptide sequence data was collected via electrospray mass spectrometry (ESI-MS) and matrix assisted laser desorption ionization mass spectrometry (MALDI-MS). The Peaks6 program was used to sequence peptides de novo from ESI data. Although there were many high probability fragments calculated by Peaks6, one sequence had particularly high coverage. Interest in this sequence was also spurred by the documented cysteine framework, although the sequence itself was novel. MALDI MS/MS data was manually interpreted, then sent to a separate investigator to interpret blinded. From these separate interpretations, multiple possible sequences were derived, of which three will be synthesized and tested for bioactivity in future work. This work not only documents peptide sequences and fragments derived from mass spectrometry, but also includes a commentary on mass spectrometry limitations encountered during sequencing.