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Structural basis of the selective block of Kv1.2 by maurotoxin from computer simulations

Rong Chen1, Shin-Ho Chung

  • 1Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia. rong.chen@anu.edu.au

Plos One
|October 17, 2012
PubMed

Insights

Maurotoxin (MTx) selectively blocks the Kv1.2 potassium channel by binding to its outer vestibule. Molecular dynamics simulations reveal MTx

Area of Science:

  • Biophysics
  • Molecular Biology
  • Pharmacology

Background:

  • Maurotoxin (MTx) is a 34-residue polypeptide from scorpion venom.
  • MTx selectively inhibits the Kv1.2 voltage-gated potassium channel by blocking ion conduction.

Purpose of the Study:

  • To investigate the binding modes of MTx to Kv1.1, Kv1.2, and Kv1.3 channels.
  • To elucidate the molecular mechanisms underlying MTx's selectivity for Kv1.2.

Main Methods:

  • Molecular dynamics (MD) simulations were employed as a docking method.
  • Potential of Mean Force (PMF) calculations were performed.

Main Results:

  • MTx exhibits stronger electrostatic interactions with the Kv1.2 outer vestibule compared to Kv1.1 and Kv1.3.
  • The binding is dynamic, with salt bridges forming and breaking within 20 ns.
  • PMF calculations yielded IC50 values of 6 µM (Kv1.1), 0.6 nM (Kv1.2), and 18 µM (Kv1.3).

Conclusions:

  • MTx selectivity for Kv1.2 is attributed to favorable electrostatic interactions and the specific shape of the channel's outer vestibule.
  • The distinct binding orientations of MTx contribute to its channel selectivity.
  • The study provides insights into toxin-potassium channel interactions at a molecular level.

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