Molecular Dynamics Studies of Ion Permeation in VDAC

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Issue Date
2011-02-02Author
Rui, Huan
Lee, Kyu, II
Pastor, Richard W.
Im, Wonpil
Publisher
Elsevier
Type
Article
Article Version
Scholarly/refereed, publisher version
Metadata
Show full item recordAbstract
The voltage-dependent anion channel (VDAC) in the outer membrane of mitochondria serves an essential role in the transport of metabolites and electrolytes between the cell matrix and mitochondria. To examine its structure, dynamics, and the mechanisms underlying its electrophysiological properties, we performed a total of 1.77 μs molecular dynamics simulations of human VDAC isoform 1 in DOPE/DOPC mixed bilayers in 1 M KCl solution with transmembrane potentials of 0, ±25, ±50, ±75, and ±100 mV. The calculated conductance and ion selectivity are in good agreement with the experimental measurements. In addition, ion density distributions inside the channel reveal possible pathways for different ion species. Based on these observations, a mechanism underlying the anion selectivity is proposed; both ion species are transported across the channel, but the rate for K+ is smaller than that for Cl− because of the attractive interactions between K+ and residues on the channel wall. This difference leads to the anion selectivity of VDAC.
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This is the publisher's version. Copyright 2011 by Elsevier.
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Citation
Rui, Huan, Kyu Il Lee, Richard W. Pastor, and Wonpil Im. "Molecular Dynamics Studies of Ion Permeation in VDAC." Biophysical Journal 100.3 (2011): 602-10. http://dx.doi.org/10.1016/j.bpj.2010.12.3711.
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