3TLT image
Entry Detail
PDB ID:
3TLT
Title:
The GLIC pentameric Ligand-Gated Ion Channel H11'F mutant in a locally-closed conformation (LC1 subtype)
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2011-08-30
Release Date:
2012-05-16
Method Details:
Experimental Method:
Resolution:
3.30 Å
R-Value Free:
0.24
R-Value Work:
0.22
R-Value Observed:
0.22
Space Group:
C 1 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Glr4197 protein
Mutations:H277F
Chain IDs:A, B, C, D, E
Chain Length:321
Number of Molecules:5
Biological Source:Gloeobacter violaceus
Primary Citation
A locally closed conformation of a bacterial pentameric proton-gated ion channel.
Nat.Struct.Mol.Biol. 19 642 649 (2012)
PMID: 22580559 DOI: 10.1038/nsmb.2307

Abstact

Pentameric ligand-gated ion channels mediate signal transduction through conformational transitions between closed-pore and open-pore states. To stabilize a closed conformation of GLIC, a bacterial proton-gated homolog from Gloeobacter violaceus whose open structure is known, we separately generated either four cross-links or two single mutations. We found all six mutants to be in the same 'locally closed' conformation using X-ray crystallography, sharing most of the features of the open form but showing a locally closed pore as a result of a concerted bending of all of its M2 helices. The mutants adopt several variant conformations of the M2-M3 loop, and in all cases an interacting lipid that is observed in the open form disappears. A single cross-linked mutant is functional, according to electrophysiology, and the locally closed structure of this mutant indicates that it has an increased flexibility. Further cross-linking, accessibility and molecular dynamics data suggest that the locally closed form is a functionally relevant conformation that occurs during allosteric gating transitions.

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