Potassium permeation through the KcsA channel: a density functional study.
We present a theoretical study on structural and electronic aspects of K+ permeation through the binding sites of the KcsA channel's selectivity filter. Density functional calculations are carried out on models taken from selected snapshots of a molecular dynamics simulation recently reported [FEBS Lett. 477 (2000) 37]. During the translocation process from one binding site to the other, the coordination number of the permeating K+ ion turns out to decrease and K+ ion polarizes significantly its ligands, backbone carbonyl groups and a water molecule. K+-induced polarization increases significantly at the transition state (TS) between the two binding sites. These findings suggest that polarization effects play a significant role in the microscopic mechanisms regulating potassium permeation.
Guidoni
Leonardo
L
Istituto Nazionale per la Fisica della Materia (INFM), Italy and International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy.
Carloni
Paolo
P
D001426:Bacterial Proteins; D001665:Binding Sites; D002414:Cations, Monovalent; D017136:Ion Transport; D008024:Ligands; D008958:Models, Molecular; D011188:Potassium / Q000737:chemistry*; D015221:Potassium Channels / Q000737:chemistry*; D011789:Quantum Theory; D013302:Streptomyces
D001426:Bacterial Proteins; D002414:Cations, Monovalent; D008024:Ligands; D015221:Potassium Channels; C107790:prokaryotic potassium channel; D011188:Potassium