3S3X: Structure of chicken acid-sensing ion channel 1 AT 3.0 A resolution in complex with psalmotoxin

Citation:
Abstract
Venom-derived peptide toxins can modify the gating characteristics of excitatory channels in neurons. How they bind and interfere with the flow of ions without directly blocking the ion permeation pathway remains elusive. Here we report the crystal structure of the trimeric chicken Acid-sensing ion channel 1 in complex with the highly selective gating modifier Psalmotoxin 1 at 3.0 A resolution. The structure reveals the molecular interactions of three toxin molecules binding at the proton-sensitive acidic pockets of Acid-sensing ion channel 1 and electron density consistent with a cation trapped in the central vestibule above the ion pathway. A hydrophobic patch and a basic cluster are the key structural elements of Psalmotoxin 1 binding, locking two separate regulatory regions in their relative, desensitized-like arrangement. Our results provide a general concept for gating modifier toxin binding suggesting that both surface motifs are required to modify the gating characteristics of an ion channel.
PDB ID: 3S3XDownload
MMDB ID: 99822
PDB Deposition Date: 2011/5/18
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 2.99  Å
Source Organism:
Gallus gallus
Similar Structures:
Biological Unit for 3S3X: hexameric; determined by author and by software (PISA)
Molecular Components in 3S3X
Label Count Molecule
Proteins (6 molecules)
3
Amiloride-sensitive Cation Channel 2, Neuronal(Gene symbol: ASIC1)
Molecule annotation
3
Psalmotoxin-1
Molecule annotation
Chemicals (10 molecules)
1
6
2
2
3
1
4
1
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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