Structure of a Bacterial Cyclic Nucleotide Regulated Ion Channel

Experimental Data Snapshot

  • Resolution: 3.10 Å
  • R-Value Free: 0.286 
  • R-Value Work: 0.276 
  • R-Value Observed: 0.276 

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Structure of the transmembrane regions of a bacterial cyclic nucleotide-regulated channel.

Clayton, G.M.Altieri, S.Heginbotham, L.Unger, V.M.Morais-Cabral, J.H.

(2008) Proc Natl Acad Sci U S A 105: 1511-1515

  • DOI: https://doi.org/10.1073/pnas.0711533105
  • Primary Citation of Related Structures:  
    2ZD9, 3BEH

  • PubMed Abstract: 

    The six-transmembrane helix (6 TM) tetrameric cation channels form the largest ion channel family, some members of which are voltage-gated and others are not. There are no reported channel structures to match the wealth of functional data on the non-voltage-gated members. We determined the structure of the transmembrane regions of the bacterial cyclic nucleotide-regulated channel MlotiK1, a non-voltage-gated 6 TM channel. The structure showed how the S1-S4 domain and its associated linker can serve as a clamp to constrain the gate of the pore and possibly function in concert with ligand-binding domains to regulate the opening of the pore. The structure also led us to hypothesize a new mechanism by which motions of the S6 inner helices can gate the ion conduction pathway at a position along the pore closer to the selectivity filter than the canonical helix bundle crossing.

  • Organizational Affiliation

    Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, CT 06520, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Mll3241 protein
A, B, C, D
355Mesorhizobium lotiMutation(s): 0 
Membrane Entity: Yes 
Find proteins for Q98GN8 (Mesorhizobium japonicum (strain LMG 29417 / CECT 9101 / MAFF 303099))
Explore Q98GN8 
Go to UniProtKB:  Q98GN8
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ98GN8
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.10 Å
  • R-Value Free: 0.286 
  • R-Value Work: 0.276 
  • R-Value Observed: 0.276 
  • Space Group: H 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 282.73α = 90
b = 282.73β = 90
c = 105.46γ = 120
Software Package:
Software NamePurpose
XSCALEdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-01-15
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2024-02-21
    Changes: Data collection, Database references, Derived calculations