Selective exclusion and selective binding both contribute to ion selectivity in KcsA, a model potassium channel

Non-Equilibrium Dynamics Contribute to Ion Selectivity in the KcsA Channel

The ability of biological ion channels to conduct selected ions across cell membranes is critical for the survival of both animal and bacterial cells. Numerous investigations of ion selectivity have been conducted over more than 50 years, yet the mechanisms whereby the channels select certain ions and reject others are not well understood. Here we report a new application of Jarzynski's Equalit...

Thermodynamics of ion selectivity in the KcsA K+ channel

Selective Binding of Cyclic Nanopeptide with Halides and Ion Pairs; a DFT-D3 Study

In this article, theoretical studies on the selective complexation of the halide ions (F¯, Cl¯ and Br¯) and ion pairs (Na+F¯, Na+Cl¯ and Na+Br¯) with the cyclic nano-hexapeptide (CP) composed of L-proline have been performed in the gas phase. In order to calculate the dispersion interaction energies of the CP and ions, DFT-D3 calculations at the M05-2X-D3/6-31G(d) level was employed. Based on t...

Exploring the origin of the ion selectivity of the KcsA potassium channel.

The availability of structural information about biological ion channels provides an opportunity to gain a detailed understanding of the control of ion selectivity by biological systems. However, accomplishing this task by computer simulation approaches is very challenging. First, although the activation barriers for ion transport can be evaluated by microscopic simulations, it is hard to obtai...

KcsA: It’s a Potassium Channel

Ion conduction and selectivity properties of KcsA, a bacterial ion channel of known structure, were studied in a planar lipid bilayer system at the single-channel level. Selectivity sequences for permeant ions were determined by symmetrical solution conductance (K Rb , NH 4 , Tl Cs , Na , Li ) and by reversal potentials under bi-ionic or mixed-ion conditions (Tl K Rb NH 4 Na , Li ). Determinati...