3UQ4

X-ray structure of a pentameric ligand gated ion channel from Erwinia chrysanthemi (ELIC) mutant F247L (F16L)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.5 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.215 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Mutations that stabilize the open state of the Erwinia chrisanthemi ligand-gated ion channel fail to change the conformation of the pore domain in crystals.

Gonzalez-Gutierrez, G.Lukk, T.Agarwal, V.Papke, D.Nair, S.K.Grosman, C.

(2012) Proc.Natl.Acad.Sci.USA 109: 6331-6336

  • DOI: 10.1073/pnas.1119268109
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The determination of structural models of the various stable states of an ion channel is a key step toward the characterization of its conformational dynamics. In the case of nicotinic-type receptors, different structures have been solved but, thus f ...

    The determination of structural models of the various stable states of an ion channel is a key step toward the characterization of its conformational dynamics. In the case of nicotinic-type receptors, different structures have been solved but, thus far, these different models have been obtained from different members of the superfamily. In the case of the bacterial member ELIC, a cysteamine-gated channel from Erwinia chrisanthemi, a structural model of the protein in the absence of activating ligand (and thus, conceivably corresponding to the closed state of this channel) has been previously generated. In this article, electrophysiological characterization of ELIC mutants allowed us to identify pore mutations that slow down the time course of desensitization to the extent that the channel seems not to desensitize at all for the duration of the agonist applications (>20 min). Thus, it seems reasonable to conclude that the probability of ELIC occupying the closed state is much lower for the ligand-bound mutants than for the unliganded wild-type channel. To gain insight into the conformation adopted by ELIC under these conditions, we solved the crystal structures of two of these mutants in the presence of a concentration of cysteamine that elicits an intracluster open probability of >0.9. Curiously, the obtained structural models turned out to be nearly indistinguishable from the model of the wild-type channel in the absence of bound agonist. Overall, our findings bring to light the limited power of functional studies in intact membranes when it comes to inferring the functional state of a channel in a crystal, at least in the case of the nicotinic-receptor superfamily.


    Organizational Affiliation

    Department of Molecular and Integrative Physiology, Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Gamma-aminobutyric-acid receptor subunit beta-1
A, B, C, D, E, F, G, H, I, J
324Dickeya dadantii (strain 3937)Mutation(s): 1 
Find proteins for E0SJQ4 (Dickeya dadantii (strain 3937))
Go to UniProtKB:  E0SJQ4
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NA
Query on NA

Download SDF File 
Download CCD File 
A, F
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.5 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.215 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 105.350α = 90.00
b = 266.940β = 109.60
c = 110.840γ = 90.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
XDSdata reduction
PHENIXrefinement
REFMACrefinement
XSCALEdata scaling
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-04-04
    Type: Initial release
  • Version 1.1: 2012-04-18
    Type: Database references
  • Version 1.2: 2012-05-02
    Type: Database references