Mass spectrometric identification and denovo sequencing of novel conotoxins from vermivorous cone snail (Conus inscriptus), and preliminary screening of its venom for biological activities in vitro and in vivo.

Abstract

Venom of Conus inscriptus, a vermivorous cone snail found abundantly in the southern coastal waters was studied to yield conotoxins through proteomic analysis. A total of 37 conotoxins (4 with single disulfide bonds, 20 with two disulfide bonds and 11 three disulfide-bonded peptides) were identified using mass spectrometric analysis. Among them, amino acid sequences of 11 novel conopeptides with one, two and three disulfides belonging to different classes were derived through manual de novo sequencing. Based on the established primary sequence, they were pharmacologically classified into α conotoxins, µ conotoxins and contryphans. Except In1696 all other conopeptides have undergone C-terminal amidation. The natural venom exhibited 50% lethality at 304.82 µg/mL against zebrafish embryo and 130.31 µg/mL against brine shrimp nauplii. The anticonvulsant study of natural venom effectively reduced the locomotor activity against pentylenetetrazole (PTZ) treated zebrafish. This concludes that the venom peptides from Conus inscriptus exhibit potential anticonvulsant function, which leads to the discovery of lead molecules against seizures.