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A molluscivorous Conus toxin: conserved frameworks in conotoxins
D R Hillyard1, B M Olivera, S Woodward
1Marine Science Institute, University of the Philippines, Manila.
Biochemistry
|January 10, 1989
Summary
Researchers identified a novel 27-amino acid toxin from Conus textile venom that induces convulsive activity in snails and dominance behaviors in lobsters. This discovery highlights conserved cysteine motifs in cone snail toxins, suggesting broad receptor targeting mechanisms.
Area of Science:
- Marine Biology
- Biochemistry
- Neurotoxicology
Background:
- Cone snails (Conus) are marine gastropods known for their diverse venomous toxins.
- Conus venom contains a complex mixture of peptides, including conotoxins, which target ion channels and receptors.
- Understanding conotoxin structure-function relationships is crucial for developing novel therapeutics and research tools.
Purpose of the Study:
- To purify and characterize a novel toxin from the venom of Conus textile.
- To elucidate the amino acid sequence and potential structural motifs of the identified toxin.
- To investigate the physiological effects of the toxin on different animal models.
Main Methods:
- Purification of the toxin from Conus textile venom.
- Amino acid sequencing of the purified peptide.
- Confirmation of the peptide sequence via nucleotide sequencing of a cDNA clone.
- Assessment of the toxin's effects on snail and lobster behavior.
Main Results:
- A 27-amino acid peptide toxin was isolated and characterized from Conus textile venom.
- The toxin's amino acid sequence was determined as Trp-Cys-Lys-Gln-Ser-Gly-Glu-Met-Cys-Asn-Leu-Leu-Asp-Gln-Asn-Cys-Cys-Asp-Gly-Tyr-Cys-Ile-Val-Leu-Val-Cys-Thr.
- The toxin induced convulsive-like activity in snails and promoted dominant postures in subordinate lobsters.
- Conservation of cysteine residues suggests shared structural backbones (Cys-motifs) among conotoxins from different Conus species.
Conclusions:
- The identified toxin represents a novel component of Conus textile venom with distinct physiological effects.
- The conserved cysteine residues indicate that Conus toxins may utilize common structural frameworks for receptor interaction across diverse animal taxa.
- This finding supports the hypothesis that "Cys-motifs" serve as conserved structural backbones for targeting various receptors, even in toxins from different Conus venoms targeting different prey.