Ion selectivity of the anthrax toxin channel and its effect on protein translocation

Aviva Schiffmiller, Damon Anderson, Alan Finkelstein

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Anthrax toxin consists of three ~85-kD proteins: lethal factor (LF), edema factor (EF), and protective antigen (PA). PA63 (the 63-kD, C-terminal portion of PA) forms heptameric channels ((PA63)7) in planar phospholipid bilayer membranes that enable the translocation of LF and EF across the membrane. These mushroom-shaped channels consist of a globular cap domain and a 14-stranded β-barrel stem domain, with six anionic residues lining the interior of the stem to form rings of negative charges. (PA63)7 channels are highly cation selective, and, here, we investigate the effects on both cation selectivity and protein translocation of mutating each of these anionic residues to a serine. We find that although some of these mutations reduce cation selectivity, selectivity alone does not directly predict the rate of protein translocation; local changes in electrostatic forces must be considered as well.

Original languageEnglish (US)
Pages (from-to)183-192
Number of pages10
JournalJournal of General Physiology
Issue number2
StatePublished - 2015

ASJC Scopus subject areas

  • Physiology


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