Potassium and sodium ions in a potassium channel studied by molecular dynamics simulations

Citation
Pc. Biggin et al., Potassium and sodium ions in a potassium channel studied by molecular dynamics simulations, BBA-BIOMEMB, 1510(1-2), 2001, pp. 1-9
Citations number
34
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES
ISSN journal
0005-2736 → ACNP
Volume
1510
Issue
1-2
Year of publication
2001
Pages
1 - 9
Database
ISI
SICI code
0005-2736(20010209)1510:1-2<1:PASIIA>2.0.ZU;2-9
Abstract
We have performed simulations of both a single potassium ion and a single s odium ion within the pore of the bacterial potassium channel KcsA. For both ions then is a dehydration energy barrier at the cytoplasmic mouth suggest ing that the crystal structure is a closed conformation of the channel. The re is a potential energy barrier for a sodium ion in the selectivity filter that is not seen for potassium. Radial distribution functions for both ion s with the carbonyl oxygens of the selectivity filter indicate that sodium may interact more tightly with the tilter than does potassium. This suggest s that the key to the ion selectivity of KcsA is the greater dehydration en ergy of Na+ ions, and helps to explain the block of KcsA by internal Na+ io ns. (C) 2001 Elsevier Science B.V. All rights reserved.