Monte Carlo study of the effect of ion and channel size on the selectivity of a model calcium channel

D. Boda, Douglas Henderson, David D. Busath

Research output: Contribution to journalArticle

61 Citations (Scopus)

Abstract

Our earlier simulation (J. Phys. Chem. B 2000, 104, 8903) of the selectivity of a model calcium channel, where all ions were assumed to have the same diameter and the channel dimensions were fixed, is extended to allow for different ionic size and variable channel size. We find that for equal valence, the channel selects cations of the smallest size. If higher valence cations are present, the channel selects cations with the highest valence, and as a result, Ca++ will replace monovalent cations. This replacement is more efficient for larger monovalent cations than for smaller ones. This is what would be expected on the basis of the charge/space competition mechanism that has been postulated earlier. Of course, if the size ratio is very large, size might be selected over valence. In addition, we consider the effect of the channel diameter and find that narrow channels are less Ca++ selective. This suggests that the recent theory of Nonner et al. (Biophys. J. 2000, 79, 1976) is most useful for wide, but still microscopic, channels.

Original languageEnglish
Pages (from-to)11574-11577
Number of pages4
JournalJournal of Physical Chemistry B
Volume105
Issue number47
DOIs
Publication statusPublished - Nov 29 2001

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Calcium Channels
Ion Channels
Cations
calcium
Calcium
Monovalent Cations
selectivity
Positive ions
Ions
ions
cations
valence
Electric space charge
space charge

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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Monte Carlo study of the effect of ion and channel size on the selectivity of a model calcium channel. / Boda, D.; Henderson, Douglas; Busath, David D.

In: Journal of Physical Chemistry B, Vol. 105, No. 47, 29.11.2001, p. 11574-11577.

Research output: Contribution to journalArticle

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