Proteomic Analysis of the Predatory Venom of Conus striatus Reveals Novel and Population-Specific κA-Conotoxin SIVC

In Silico Conotoxin Studies: Progress and Prospects

Cone snails of the genus Conus have evolved to produce structurally distinct and functionally diverse venom peptides for defensive and predatory purposes. This nature-devised delicacy enlightened drug discovery and for decades, the bioactive cone snail venom peptides, known as conotoxins, have been widely explored for their therapeutic potential, yet we know very little about them. With the augmentation of computational algorithms from the realms of bioinformatics and machine learning, in silico strategies have made substantial contributions to facilitate conotoxin studies although still with certain limitations. In this review, we made a bibliometric analysis of in silico conotoxin studies from 2004 to 2024 and then discussed in silico strategies to not only efficiently classify conotoxin superfamilies but also speed up drug discovery from conotoxins, reveal binding modes of known conotoxin-ion channel interactions at a microscopic level and relate the mechanisms of ion channel modulation to its underlying molecular structure. We summarized the current progress of studies in this field and gave an outlook on prospects.

Structure-aided function assignment to the transcriptomic conopeptide Am931

Implementation of the next-generation technologies for gene sequencing of venom duct transcriptome has provided a large number of peptide sequences of marine cone snails. Emerging technologies on computational platforms are now rapidly evolving for the accurate predictions of the 3D structure of the polypeptide using the primary sequence. The current report aims to integrate the information derived from these two technologies to develop the concept of structure-aided function assignment of Conus peptides. The proof of the concept was demonstrated using the transcriptomic peptide Am931 of C. amadis. The 3D structure of Am931 was computed using Density Functional Theory (DFT) and the quality of the predicted structure was confirmed using 2D NMR spectroscopy of the corresponding synthetic peptide. The computed structure of Am931 aligns with the active site motif of thioredoxins, possess catalytic disulfide conformation of (+, -)AntiRHHook and selectively modulate the N-terminal Cys3 thiol. These structural features indicate that Am931 may act as a disulfide isomerase and modulate the oxidative folding of conotoxins. Synthetic peptide Am931 provides proof-of-function by exhibiting catalytic activity on the oxidative folding of α-conotoxin ImI and improving the yield of native globular fold. The approach of integration of new technologies in the Conus peptide research may help to accelerate the discovery pipeline of new/improved conotoxin functional.

Predatory and Defensive Strategies in Cone Snails

Cone snails are carnivorous marine animals that prey on fish (piscivorous), worms (vermivorous), or other mollusks (molluscivorous). They produce a complex venom mostly made of disulfide-rich conotoxins and conopeptides in a compartmentalized venom gland. The pharmacology of cone snail venom has been increasingly investigated over more than half a century. The rising interest in cone snails was initiated by the surprising high human lethality rate caused by the defensive stings of some species. Although a vast amount of information has been uncovered on their venom composition, pharmacological targets, and mode of action of conotoxins, the venom-ecology relationships are still poorly understood for many lineages. This is especially important given the relatively recent discovery that some species can use different venoms to achieve rapid prey capture and efficient deterrence of aggressors. Indeed, via an unknown mechanism, only a selected subset of conotoxins is injected depending on the intended purpose. Some of these remarkable venom variations have been characterized, often using a combination of mass spectrometry and transcriptomic methods. In this review, we present the current knowledge on such specific predatory and defensive venoms gathered from sixteen different cone snail species that belong to eight subgenera: Pionoconus, Chelyconus, Gastridium, Cylinder, Conus, Stephanoconus, Rhizoconus, and Vituliconus. Further studies are needed to help close the gap in our understanding of the evolved ecological roles of many cone snail venom peptides.