Background: Conus amadis is a carnivorous snail found abundantly in coastal waters of
India. Despite its abundance in southern coastal waters of India and the fact that most of the
conotoxin act in neuronal system, research work on Conus amadis venom was not much focused.
So we have made a brief study on the venom complex of Conus amadis to identify the library of
novel conotoxins and to screen the natural venom for neurological function.
Objective: De novo sequencing of novel conopeptides from the venom cocktail of Conus amadis
and to screen its natural venom for the presence of biological activities in zebrafish model.
Methods: Proteome based MALDI-TOF and LC-MS-MS analysis for identification of novel
conotoxins and subsequent sequencing. Due to the complex disulfide rich nature of the venom
peptides, the study also involves global chemical modification experiments of the venom extract to
unambiguously determine the sequence of novel conotoxins. Biological function analysis of natural
venom was tested in zebrafish model to ascertain anti-epileptic properties.
Results: In this study, we have identified 19 novel conotoxins containing 1, 2 & 3 disulfides,
belonging to different classes. Among them, 2 novel contryphans, 3 T-superfamily conotoxins, 2
A-superfamily conotoxins and 2 Mini M-Superfamily conotoxins were sequenced to its amino acid
level from the fragmented spectrum of singly and doubly charged parent ions using de novo
sequencing strategies. ama1054, a contryphan peptide toxin, possesses post translationally modified
bromo tryptophan at its seventh position. Except ama1251, all the sequenced peptide toxins possess
modified C-terminal amidation. Crude venom exhibited anticonvulsant properties in
pentylenetetrazole-induced seizure in zebrafish larvae, which suggested anti-epileptic property of
the venom cocktail. Acetylcholinesterase activity was also identified in the venom complex.
Conclusion: Based on the preliminary evidence, if this study is extended further through bioassay
guided purification, could possibly yield peptide toxins with anticonvulsant and other
neurologically active molecules.