The 12-transmembrane helix transporters

Curr Opin Cell Biol. 1993 Aug;5(4):708-21. doi: 10.1016/0955-0674(93)90144-f.


From the hydropathic profiles of their amino acid sequences many transport proteins are conceived to comprise 12-transmembrane alpha-helices. In only a few examples, however, is there genetical and/or biochemical evidence to support the 12-helix structure or illuminate the molecular mechanism of the transport process. A number of these transport proteins occur in evolutionarily related families, and sometimes superfamilies, indicating divergent evolution of the 12-helix structure. Other individual members or families of transport proteins are sufficiently different in amino acid sequence for their evolution to have taken place by convergence from independent ancestral origins.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Biological Transport / physiology
  • Carrier Proteins / genetics
  • Carrier Proteins / physiology*
  • Humans
  • Membranes / metabolism
  • Molecular Sequence Data
  • Protein Binding
  • Protein Structure, Secondary*
  • Terminology as Topic


  • Carrier Proteins