Why is gramicidin valence selective? A theoretical study

S. S. Sung, P. C. Jordan

    Research output: Contribution to journalArticlepeer-review

    32 Scopus citations

    Abstract

    Calculations contrasting the channel solvation energy for cesium ions and chloride ions associated with water in gramicidin-like channels are presented. The energy profile for the cation exhibits a deep well at the channel entrance; within the single file region the solvation energy is roughly constant. The anion exhibits a totally different energy profile. There is an energy barrier at the channel entrance; if the ion could surmount this barrier, it would be quite stable within the channel. At the channel entrance, the calculated solvation energy difference between anion and cation is approximately 15 kcal mol-1. This is completely consistent with the observation that chloride neither permeates nor blocks the channel since the estimated rate of ion entry would be approximately 0.01–10(-5) s-1, far slower than the rate at which the channel dimer dissociates into monomers.

    Original languageEnglish (US)
    Pages (from-to)661-672
    Number of pages12
    JournalBiophysical journal
    Volume51
    Issue number4
    DOIs
    StatePublished - 1987

    All Science Journal Classification (ASJC) codes

    • Biophysics

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