Charybdotoxin unbinding from the mKv1.3 potassium channel: A combined computational and experimental study Article

Khabiri, M, Nikouee, A, Cwiklik, L et al. (2011). Charybdotoxin unbinding from the mKv1.3 potassium channel: A combined computational and experimental study . JOURNAL OF PHYSICAL CHEMISTRY B, 115(39), 11490-11500. 10.1021/jp2061909

cited authors

  • Khabiri, M; Nikouee, A; Cwiklik, L; Grissmer, S; Ettrich, R

authors

abstract

  • Charybdotoxin, belonging to the group of so-called scorpion toxins, is a short peptide able to block many voltage-gated potassium channels, such as mKv1.3, with high affinity. We use a reliable homology model based on the high-resolution crystal structure of the 94% sequence identical homologue Kv1.2 for charybdotoxin docking followed by molecular dynamics simulations to investigate the mechanism and energetics of unbinding, tracing the behavior of the channel protein and charybdotoxin during umbrella-sampling simulations as charybdotoxin is moved away from the binding site. The potential of mean force is constructed from the umbrella sampling simulations and combined with K d and free energy values gained experimentally using the patch-clamp technique to study the free energy of binding at different ion concentrations and the mechanism of the charybdotoxin-mKv1.3 binding process. A possible charybdotoxin binding mechanism is deduced that includes an initial hydrophobic contact followed by stepwise electrostatic interactions and finally optimization of hydrogen bonds and salt bridges. © 2011 American Chemical Society.

publication date

  • October 6, 2011

published in

Digital Object Identifier (DOI)

start page

  • 11490

end page

  • 11500

volume

  • 115

issue

  • 39