Structures of membrane proteins determined at atomic resolution

J Biochem. 1998 Dec 1;124(6):1051-9. doi: 10.1093/oxfordjournals.jbchem.a022199.

Abstract

Following determination of the first crystal structure of the reaction center of Rhodopseudomonas viridis, a membrane protein, by X-ray crystal structure analysis at 3.0 A resolution, 18 X-ray crystal structures and two electron crystal structures of membrane proteins have been obtained at higher than 3.5 A resolution. Besides these integral membrane protein structures, three crystal structures of water-soluble proteins, which can enter membranes, have been determined by X-ray crystallography at high resolution. The structural features of membrane proteins have been summarized by inspecting these crystal structures. The polypeptide chain crosses the membrane in a helical conformation or a beta-strand. The central +10 A region of the transmembrane alpha-helix is dominated by hydrophobic residues. On both sides of the central region are concentrated polar aromatic residues. Charged residues are dominant around +15 A to +20 A. All the transmembrane beta-structures are found in pore-forming proteins. The central region of the transmembrane beta-structure is amphipathic with hydrophobic residues on the membrane exposed side. The distribution of amino acid residues on the membrane exposed surface of the transmembrane beta-structure is similar to that of the transmembrane alpha-helix. alpha-Helices anchoring the membrane surface region are amphipathic with hydrophobic residues inside and hydrophilic residues outside.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Bacterial Toxins / chemistry
  • Bacteriorhodopsins / chemistry
  • Cell Membrane / chemistry
  • Colicins / chemistry
  • Crystallography, X-Ray / methods
  • Humans
  • Membrane Proteins / chemistry*
  • Models, Molecular
  • Pore Forming Cytotoxic Proteins
  • Porins / chemistry
  • Potassium Channels / chemistry
  • Protein Conformation

Substances

  • Bacterial Toxins
  • Colicins
  • Membrane Proteins
  • Pore Forming Cytotoxic Proteins
  • Porins
  • Potassium Channels
  • Bacteriorhodopsins
  • aerolysin