When biochemistry meets structural biology: the cautionary tale of EmrE

Trends Biochem Sci. 2007 Jun;32(6):252-8. doi: 10.1016/j.tibs.2007.04.002. Epub 2007 Apr 23.


When biochemistry meets structural biology a more complete understanding of the mechanism of biological macromolecules is usually achieved. Several high-resolution structures of ion-coupled transporters have enriched the understanding of mechanisms of substrate recognition, translocation and coupling of substrate fluxes. However, two X-ray structures of EmrE, the smallest ion-coupled multi-drug transporter, raised questions over the veracity of the structural model and represented a cautionary tale about the difficulty of determining the 3D structures of membrane proteins and the dangers of ignoring biochemical results. The 3D structures of EmrE have since been retracted because of faulty software, but the suggestion that the protomers in the dimer are in an antiparallel topological orientation sparked controversy that is still ongoing.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Antiporters / chemistry*
  • Antiporters / drug effects
  • Crystallography, X-Ray
  • Detergents / pharmacology
  • Dimerization
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / drug effects
  • Membrane Proteins / chemistry
  • Models, Molecular
  • Protein Structure, Secondary / drug effects
  • Retraction of Publication as Topic
  • Software


  • Antiporters
  • Detergents
  • Escherichia coli Proteins
  • Membrane Proteins
  • EmrE protein, E coli