7PX2 image
Entry Detail
PDB ID:
7PX2
Keywords:
Title:
Conotoxin Mu8.1 from Conus mucronatus
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2021-10-07
Release Date:
2022-11-16
Method Details:
Experimental Method:
Resolution:
2.12 Å
R-Value Free:
0.23
R-Value Work:
0.21
R-Value Observed:
0.21
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Conotoxin Mu8.1
Chain IDs:A, B, C, D, E, F
Chain Length:89
Number of Molecules:6
Biological Source:Conus mucronatus
Ligand Molecules
Primary Citation
A previously unrecognized superfamily of macro-conotoxins includes an inhibitor of the sensory neuron calcium channel Cav2.3.
Plos Biol. 21 e3002217 e3002217 (2023)
PMID: 37535677 DOI: 10.1371/journal.pbio.3002217

Abstact

Animal venom peptides represent valuable compounds for biomedical exploration. The venoms of marine cone snails constitute a particularly rich source of peptide toxins, known as conotoxins. Here, we identify the sequence of an unusually large conotoxin, Mu8.1, which defines a new class of conotoxins evolutionarily related to the well-known con-ikot-ikots and 2 additional conotoxin classes not previously described. The crystal structure of recombinant Mu8.1 displays a saposin-like fold and shows structural similarity with con-ikot-ikot. Functional studies demonstrate that Mu8.1 curtails calcium influx in defined classes of murine somatosensory dorsal root ganglion (DRG) neurons. When tested on a variety of recombinantly expressed voltage-gated ion channels, Mu8.1 displayed the highest potency against the R-type (Cav2.3) calcium channel. Ca2+ signals from Mu8.1-sensitive DRG neurons were also inhibited by SNX-482, a known spider peptide modulator of Cav2.3 and voltage-gated K+ (Kv4) channels. Our findings highlight the potential of Mu8.1 as a molecular tool to identify and study neuronal subclasses expressing Cav2.3. Importantly, this multidisciplinary study showcases the potential of uncovering novel structures and bioactivities within the largely unexplored group of macro-conotoxins.

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Primary Citation of related structures