Isolation And Characterization Of Three Conotoxins From The South China Sea

Cone snails are predatory gastropod mollusks distributed in all tropical marine habitat with 500~700 species all over the world. There are about 100 conus species in China, mostly distributed in Xisha, Hainan islands and Taiwan water areas.Conotoxins are secreted by venom duct and theca. Conus venom has 50～200 different bioactive peptides with little overlap between species. Generally, conotoxins contain 10~40 amino acid residues with rich disulfide bond and could target a series of ion channels or recepter subtypes.Conotoxins are not only developed directly into drugs, but also used as perfect drug design templates and probes for neurobiological researches. This research is to isolate, purify and identify new conotoxins from conus textile, conus imperialis and conus marmoreus in South China Sea and lays a foundation for further researches on their physiological and pharmacological functions.The living specimens of the three conus for the isolation, purification and identification were collected from the South China Sea in Apr,2007.A series of isolation methods, such as Sephadex G-25,ion exchange and RP-HPLC were used to isolate and purify the conotoxins from the above three cone snails. 53 conotoxins were isolated, including 23, 25 and 5 peptides from conus textile, conus imperialis and conus marmoreus, respectively. The purity reaches more than 85 percent by the analysis of HPLC.The molecular weights were determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The new peptide sequences were analyzed by automatic Edman sequencr and Quatropde-Time of Flight Mass spectrometer. A total of 17 new peptides, including 8,8 and 1 novel peptides were found for the first time in conus textile, conus imperialis and conus marmoreus, respectively. The related biological activities were predicted based on their sequence features.