Secretion and maturation of conotoxins in the venom ducts of Conus textile.

The 700 or more species of cone snail attack prey by employing complex venom which can vary considerably both within species and from one species to another. Cone snail venom is remarkable for the high proportion of conotoxins with varied post-translational modifications (PTMs) and for the production of more diverse toxin scaffolds than any other known venomous animal. The venom gland, which is several times longer than its shell, is also unique in being tubular. These unusual characteristics both raise questions, and provide the opportunity for research, concerning the secretion and maturation of conotoxins along the venom duct, a process which is currently not fully understood. This research uses the two mass spectrometric techniques of isotope Coded Affinity Tagging (ICAT) and label-free quantification to study each of five portions of the venom duct of Conus textile snails from New Caledonia. Fifteen conotoxins, several with different post-translational modifications (PTMs) were identified and quantified. One hundred and forty three non-identified conotoxins were also quantified. Distinctive patterns emerged, with the largest group of conotoxins increasing, then peaking in the central-proximal part, before decreasing; whilst the second largest group peaked in the distal region, generally displaying nothing in the first parts. Conotoxins from different superfamilies were commonly found to have similar distributions. A new conotoxin, PCCSKLHDNSCCGL*, was sequenced. A comparison is made with other studies to see how the process varies in cone snails from different regions.