4YKI

Mnemiopsis leidyi ML032222a iGluR LBD glycine complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.21 Å
  • R-Value Free: 0.161 
  • R-Value Work: 0.134 
  • R-Value Observed: 0.135 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Glycine activated ion channel subunits encoded by ctenophore glutamate receptor genes.

Alberstein, R.Grey, R.Zimmet, A.Simmons, D.K.Mayer, M.L.

(2015) Proc Natl Acad Sci U S A 112: E6048-E6057

  • DOI: https://doi.org/10.1073/pnas.1513771112
  • Primary Citation of Related Structures:  
    4YKI, 4YKJ, 4YKK, 4YKP, 4ZDM

  • PubMed Abstract: 

    Recent genome projects for ctenophores have revealed the presence of numerous ionotropic glutamate receptors (iGluRs) in Mnemiopsis leidyi and Pleurobrachia bachei, among our earliest metazoan ancestors. Sequence alignments and phylogenetic analysis show that these form a distinct clade from the well-characterized AMPA, kainate, and NMDA iGluR subtypes found in vertebrates. Although annotated as glutamate and kainate receptors, crystal structures of the ML032222a and PbiGluR3 ligand-binding domains (LBDs) reveal endogenous glycine in the binding pocket, whereas ligand-binding assays show that glycine binds with nanomolar affinity; biochemical assays and structural analysis establish that glutamate is occluded from the binding cavity. Further analysis reveals ctenophore-specific features, such as an interdomain Arg-Glu salt bridge, present only in subunits that bind glycine, but also a conserved disulfide in loop 1 of the LBD that is found in all vertebrate NMDA but not AMPA or kainate receptors. We hypothesize that ctenophore iGluRs are related to an early ancestor of NMDA receptors, suggesting a common evolutionary path for ctenophores and bilaterian species, and suggest that future work should consider both glycine and glutamate as candidate neurotransmitters in ctenophore species.


  • Organizational Affiliation

    Laboratory of Cellular and Molecular Neurophysiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892;


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ML032222a iGluR
A, B
256Mnemiopsis leidyiMutation(s): 0 
Gene Names: ML032222a
UniProt
Find proteins for A0A0R4I973 (Mnemiopsis leidyi)
Explore A0A0R4I973 
Go to UniProtKB:  A0A0R4I973
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A0R4I973
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.21 Å
  • R-Value Free: 0.161 
  • R-Value Work: 0.134 
  • R-Value Observed: 0.135 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.944α = 90
b = 123.388β = 111.84
c = 54.319γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-10-21
    Type: Initial release
  • Version 1.1: 2015-10-28
    Changes: Database references
  • Version 1.2: 2015-11-18
    Changes: Database references
  • Version 1.3: 2023-09-27
    Changes: Data collection, Database references, Derived calculations, Refinement description