2I68

Cryo-EM based theoretical model structure of transmembrane domain of the multidrug-resistance antiporter from E. coli EmrE


Experimental Data Snapshot

  • Method: ELECTRON CRYSTALLOGRAPHY
  • Resolution: 7.5 Å
  • Aggregation State: 2D ARRAY 
  • Reconstruction Method: CRYSTALLOGRAPHY 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Quasi-symmetry in the Cryo-EM Structure of EmrE Provides the Key to Modeling its Transmembrane Domain

Fleishman, S.J.Harrington, S.E.Enosh, A.Halperin, D.Tate, C.G.Ben-Tal, N.

(2006) J.Mol.Biol. 364: 54-67

  • DOI: 10.1016/j.jmb.2006.08.072

  • PubMed Abstract: 
  • Small multidrug resistance (SMR) transporters contribute to bacterial resistance by coupling the efflux of a wide range of toxic aromatic cations, some of which are commonly used as antibiotics and antiseptics, to proton influx. EmrE is a prototypica ...

    Small multidrug resistance (SMR) transporters contribute to bacterial resistance by coupling the efflux of a wide range of toxic aromatic cations, some of which are commonly used as antibiotics and antiseptics, to proton influx. EmrE is a prototypical small multidrug resistance transporter comprising four transmembrane segments (M1-M4) that forms dimers. It was suggested recently that EmrE molecules in the dimer have different topologies, i.e. monomers have opposite orientations with respect to the membrane plane. A 3-D structure of EmrE acquired by electron cryo-microscopy (cryo-EM) at 7.5 Angstroms resolution in the membrane plane showed that parts of the structure are related by quasi-symmetry. We used this symmetry relationship, combined with sequence conservation data, to assign the transmembrane segments in EmrE to the densities seen in the cryo-EM structure. A C alpha model of the transmembrane region was constructed by considering the evolutionary conservation pattern of each helix. The model is validated by much of the biochemical data on EmrE with most of the positions that were identified as affecting substrate translocation being located around the substrate-binding cavity. A suggested mechanism for proton-coupled substrate translocation in small multidrug resistance antiporters provides a mechanistic rationale to the experimentally observed inverted topology.


    Related Citations: 
    • Three-dimensional structure of the bacterial multidrug transporter EmrE shows it is an asymmetric homodimer
      Ubarretxena-Belandia, I.,Baldwin, J.M.,Schuldiner, S.,Tate, C.G.
      (2003) Embo J. 22: 6175


    Organizational Affiliation

    Department of Biochemistry, George S Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv, Israel.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Protein emrE
A, B
137Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: emrE (eb, mvrC)
Find proteins for P23895 (Escherichia coli (strain K12))
Go to UniProtKB:  P23895
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON CRYSTALLOGRAPHY
  • Resolution: 7.5 Å
  • Aggregation State: 2D ARRAY 
  • Reconstruction Method: CRYSTALLOGRAPHY 

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-10-03
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance