Cation transport: An example of structural based selectivity

F. Tian, T. A. Cross

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


Through the high-resolution structure of the gramicidin A channel in lamellar phase lipids and the characterization of specific ion peptide interactions, fundamental principles for ion channel selectivity and conductance efficiency are illustrated with atomic resolution detail. Delocalized cation binding in the first turn of the helix reduces the unfavorable entropy contribution upon binding. Stepwise dehydration minimizes the energy barrier for cation entry and provides valence selectivity in this channel. Three or more water molecules in the monovalent cation binding site result in flexibility in the cation solvation environment causing weak cation size selectivity. Lack of cation induced structural modification avoids the formation of a significant energy barrier, thus permitting efficient cation transport.

Original languageEnglish (US)
Pages (from-to)1993-2003
Number of pages11
JournalJournal of Molecular Biology
Issue number5
StatePublished - Feb 5 1999

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Structural Biology
  • Molecular Biology


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