PUBLICATION

Conformational transitions and allosteric modulation in a heteromeric glycine receptor

Authors
Gibbs, E., Klemm, E., Seiferth, D., Kumar, A., Ilca, S.L., Biggin, P.C., Chakrapani, S.
ID
ZDB-PUB-230315-33
Date
2023
Source
Nature communications   14: 13631363 (Journal)
Registered Authors
Keywords
none
MeSH Terms
  • Animals
  • Strychnine*/pharmacology
  • Ivermectin/pharmacology
  • Zebrafish/metabolism
  • Glycine/metabolism
  • Receptors, Glycine*/metabolism
PubMed
36914669 Full text @ Nat. Commun.
Abstract
Glycine Receptors (GlyRs) provide inhibitory neuronal input in the spinal cord and brainstem, which is critical for muscle coordination and sensory perception. Synaptic GlyRs are a heteromeric assembly of α and β subunits. Here we present cryo-EM structures of full-length zebrafish α1βBGlyR in the presence of an antagonist (strychnine), agonist (glycine), or agonist with a positive allosteric modulator (glycine/ivermectin). Each structure shows a distinct pore conformation with varying degrees of asymmetry. Molecular dynamic simulations found the structures were in a closed (strychnine) and desensitized states (glycine and glycine/ivermectin). Ivermectin binds at all five interfaces, but in a distinct binding pose at the β-α interface. Subunit-specific features were sufficient to solve structures without a fiduciary marker and to confirm the 4α:1β stoichiometry recently observed. We also report features of the extracellular and intracellular domains. Together, our results show distinct compositional and conformational properties of α1βGlyR and provide a framework for further study of this physiologically important channel.
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