Polarization effects and charge transfer in the KcsA potassium channel

Denis Bucher, Simone Raugei, Leonardo Guidoni, Matteo Dal Peraro, Ursula Rothlisberger, Paolo Carloni, Michael L. Klein

Research output: Contribution to journalArticlepeer-review

76 Citations (Scopus)


The electronic structure of the selectivity filter of KcsA K+ channel is investigated by density functional theory (DFT/BLYP) and QM/MM methods. The quantum part includes the selectivity filter, which is polarized by the electrostatic field of the environment treated with the Amber force field. The details of the electronic structure were investigated using the maximally localized Wannier function centers of charge and Bader's atoms in molecules charge analysis. Our results show that the channel backbone carbonyl groups are largely polarized and that there is a sizeable charge transfer from the backbone to the cations. These effects are expected to be important for an accurate description of the carbonyl groups and the ion-ion electrostatic repulsion, which have been proposed to play a central role for the selectivity mechanism of the channel [S.Y. Noskov, S. Berneche, B. Roux, Control of ion selectivity in potassium channels by electrostatic and dynamic properties of carbonyl ligands. Nature 431 (2004) 830-834].

Original languageEnglish
Pages (from-to)292-301
Number of pages10
JournalBiophysical Chemistry
Issue number3
Publication statusPublished - Dec 1 2006


  • Bader charge
  • Charge transfer
  • First principles molecular dynamics
  • KcsA
  • Polarization effects
  • Potassium channel
  • Wannier centers

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Organic Chemistry

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