Isolation and characterization of five novel disulfide-poor conopeptides from Conus marmoreus venom

Background: Conopeptides from cone snail venom have aroused great interest related to the discovery of novel bioactive candidates, due to their excellent prospects for the treatment of various health problems such as pain, addiction, psychosis and epilepsy. In order to explore novel biopeptides, we investigated the structure and function of five novel conopeptides isolated from the venom of Conus marmoreus from South China Sea. Methods: C. marmoreus crude venom was prepared, fractionated and purified by HPLC system. The primary sequences of the five novel disulfide-poor conopeptides Mr-1 to Mr-5 were identified by comprehensive analysis of de novo MALDI-TOF tandem mass spectrometry and Edman degradation data. In order to investigate their function, these five conopeptides were synthesized by Fmoc-SPPS chemistry, and their biological effects at several heterologous rat nicotinic acetylcholine receptor (nAChR) subtypes (α1β1δε, α3β2, α3β4, α4β2) were determined by electrophysiological technique. Results: Five novel disulfide-poor conopeptides were identified and named as follows: Mr-1 (DWEYHAHPKPNSFWT), Mr-2 (YPTRAYPSNKFG), Mr-3 (NVIQAPAQSVAPP NTST), Mr-4 [KENVLNKLKSK(L/I)] and Mr-5 [NAVAAAN(L/I)PG(L/I)V]. None of them contains a disulfide bond. The sequences of conopeptides Mr-2 to Mr-5 do not belong to any category of the known disulfide-poor conopeptides. No significant activity against the above nAChR subtypes were observed for the five conopeptides at 100 µM. Conclusion: We purified and structurally characterized five novel disulfide-poor conopeptides from C. marmoreus crude venom and first investigated their nAChR inhibitory effects. This work expanded our knowledge on the structure and function of disulfide-poor conopeptides from this cone snail venom.(AU)

Proteomic analysis of Red Sea Conus taeniatus venom reveals potential biological applications

Diverse and unique bioactive neurotoxins known as conopeptides or conotoxins are produced by venomous marine cone snails. Currently, these small and stable molecules are of great importance as research tools and platforms for discovering new drugs and therapeutics. Therefore, the characterization of Conus venom is of great significance, especially for poorly studied species. Methods: In this study, we used bioanalytical techniques to determine the venom profile and emphasize the functional composition of conopeptides in Conus taeniatus, a neglected worm-hunting cone snail. Results: The proteomic analysis revealed that 84.0% of the venom proteins were between 500 and 4,000 Da, and 16.0% were > 4,000 Da. In C. taeniatus venom, 234 peptide fragments were identified and classified as conotoxin precursors or non-conotoxin proteins. In this process, 153 conotoxin precursors were identified and matched to 23 conotoxin precursors and hormone superfamilies. Notably, the four conotoxin superfamilies T (22.87%), O1 (17.65%), M (13.1%) and O2 (9.8%) were the most abundant peptides in C. taeniatus venom, accounting for 63.40% of the total conotoxin diversity. On the other hand, 48 non-conotoxin proteins were identified in the venom of C. taeniatus. Moreover, several possibly biologically active peptide matches were identified, and putative applications of the peptides were assigned. Conclusion: Our study showed that the composition of the C. taeniatus-derived proteome is comparable to that of other Conus species and contains an effective mix of toxins, ionic channel inhibitors and antimicrobials. Additionally, it provides a guidepost for identifying novel conopeptides from the venom of C. taeniatus and discovering conopeptides of potential pharmaceutical importance.(AU)

Proteomic analysis of Red Sea Conus taeniatus venom reveals potential biological applications

Abstract Background: Diverse and unique bioactive neurotoxins known as conopeptides or conotoxins are produced by venomous marine cone snails. Currently, these small and stable molecules are of great importance as research tools and platforms for discovering new drugs and therapeutics. Therefore, the characterization of Conus venom is of great significance, especially for poorly studied species. Methods: In this study, we used bioanalytical techniques to determine the venom profile and emphasize the functional composition of conopeptides in Conus taeniatus, a neglected worm-hunting cone snail. Results: The proteomic analysis revealed that 84.0% of the venom proteins were between 500 and 4,000 Da, and 16.0% were > 4,000 Da. In C. taeniatus venom, 234 peptide fragments were identified and classified as conotoxin precursors or non-conotoxin proteins. In this process, 153 conotoxin precursors were identified and matched to 23 conotoxin precursors and hormone superfamilies. Notably, the four conotoxin superfamilies T (22.87%), O1 (17.65%), M (13.1%) and O2 (9.8%) were the most abundant peptides in C. taeniatus venom, accounting for 63.40% of the total conotoxin diversity. On the other hand, 48 non-conotoxin proteins were identified in the venom of C. taeniatus. Moreover, several possibly biologically active peptide matches were identified, and putative applications of the peptides were assigned. Conclusion: Our study showed that the composition of the C. taeniatus-derived proteome is comparable to that of other Conus species and contains an effective mix of toxins, ionic channel inhibitors and antimicrobials. Additionally, it provides a guidepost for identifying novel conopeptides from the venom of C. taeniatus and discovering conopeptides of potential pharmaceutical importance.