Structure of the outer membrane protein A transmembrane domain

Nat Struct Biol. 1998 Nov;5(11):1013-7. doi: 10.1038/2983.


The outer membrane protein A of Escherichia coli (OmpA) is an intensely studied example in the field of membrane protein folding. We have determined the structure of the OmpA transmembrane domain consisting of residues 1-171, by X-ray diffraction analysis, to a resolution of 2.5 A. It consists of a regular, extended eight-stranded beta-barrel and appears to be constructed like an inverse micelle with large water-filled cavities, but does not form a pore. Surprisingly, the cavities seem to be highly conserved during evolution. The structure corroborates the concept that all outer membrane proteins consist of beta-barrels. The structure constitutes a beta-barrel membrane anchor that appears to be the outer membrane equivalent of the single-chain alpha-helix anchor of the inner membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Outer Membrane Proteins / chemistry*
  • Crystallography, X-Ray
  • Escherichia coli / chemistry*
  • Lipid Bilayers
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid


  • Bacterial Outer Membrane Proteins
  • Lipid Bilayers
  • OMPA outer membrane proteins

Associated data

  • PDB/1BXW