Combined Effect of Pore Radius and Protein Dielectric Coefficient on the Selectivity of a Calcium Channel

Dezső Boda, Mónika Valiskó, Bob Eisenberg, Wolfgang Nonner, Douglas Henderson, and Dirk Gillespie
Phys. Rev. Lett. 98, 168102 – Published 17 April 2007

Abstract

Calcium-selective ion channels often contain a selectivity filter made of similar amino acids, rich in carboxlylates, although the Ca2+ affinities of these channels range from micromolar to millimolar. To understand the physical mechanism for this range of affinities, we use grand canonical Monte Carlo simulations to study the competition of Na+ and Ca2+ in the selectivity filter of a reduced model of a Ca channel. We show that Ca2+ affinity is increased dramatically when both the volume and dielectric coefficient of the protein are reduced.

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  • Received 28 August 2006

DOI:https://doi.org/10.1103/PhysRevLett.98.168102

©2007 American Physical Society

Authors & Affiliations

Dezső Boda1,2,*, Mónika Valiskó2, Bob Eisenberg1, Wolfgang Nonner3, Douglas Henderson4, and Dirk Gillespie1

  • 1Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois 60612, USA
  • 2Department of Physical Chemistry, University of Pannonia, P. O. Box 158, H-8201 Veszprém, Hungary
  • 3Department of Physiology and Biophysics, University of Miami School of Medicine, Miami, Florida 33101, USA
  • 4Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA

  • *Corresponding author. Electronic address: dezso_boda@rush.edu

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Vol. 98, Iss. 16 — 20 April 2007

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