Evidence for Elapid Neurotoxins in the Vipers Echis carinatus and Echis ocellatus

Echis carinatus and E. ocellatus belong to the most deadly snakes. We investigated pooled venom using data-independent and target high-resolution mass spectrometry. Since the reference protein databases for both species were not comprehensive, we additionally searched those of higher orders. Interestingly, considerable amounts of three-finger toxins including long neurotoxin 1, weak toxins and short neurotoxins were detected in E. carinatus, which are hallmarks of elapid, not viperid, snakes. The presence of these toxins was confirmed by manual fragment ion analysis of selected peptides. The larger proteins snake venom vascular endothelial growth factor toxin barietin and basic phospholipase A2 ammodytoxin C were also found in both venoms with sequences not known in this genus so far. This study provides new confirmed peptide sequence information for 11 smaller proteins of E. carinatus and E. ocellatus.