7LQR image
Entry Detail
PDB ID:
7LQR
Keywords:
Title:
Structure of conotoxin CIC
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2021-02-15
Release Date:
2021-04-21
Method Details:
Experimental Method:
Conformers Calculated:
100
Conformers Submitted:
20
Selection Criteria:
target function
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Alpha-conotoxin CIC
Chain IDs:A
Chain Length:21
Number of Molecules:1
Biological Source:Conus catus
Ligand Molecules
Primary Citation
Synthesis, Structural and Pharmacological Characterizations of CIC, a Novel alpha-Conotoxin with an Extended N-Terminal Tail.
Mar Drugs 19 ? ? (2021)
PMID: 33801301 DOI: 10.3390/md19030141

Abstact

Cone snails are venomous marine predators that rely on fast-acting venom to subdue their prey and defend against aggressors. The conotoxins produced in the venom gland are small disulfide-rich peptides with high affinity and selectivity for their pharmacological targets. A dominant group comprises α-conotoxins, targeting nicotinic acetylcholine receptors. Here, we report on the synthesis, structure determination and biological activity of a novel α-conotoxin, CIC, found in the predatory venom of the piscivorous species Conus catus and its truncated mutant Δ-CIC. CIC is a 4/7 α-conotoxin with an unusual extended N-terminal tail. High-resolution NMR spectroscopy shows a major influence of the N-terminal tail on the apparent rigidity of the three-dimensional structure of CIC compared to the more flexible Δ-CIC. Surprisingly, this effect on the structure does not alter the biological activity, since both peptides selectively inhibit α3β2 and α6/α3β2β3 nAChRs with almost identical sub- to low micromolar inhibition constants. Our results suggest that the N-terminal part of α-conotoxins can accommodate chemical modifications without affecting their pharmacology.

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