A simple method for the determination of the pore radius of ion channels in planar lipid bilayer membranes

• Published in: FEMS microbiology immunology Vol. 105; no. 1-3; pp. 93 - 100
• Main Authors: KRASILNIKOV, O. V, SABIROV, R. Z, TERNOVSKY, V. I, MERZLIAK, P. G, MURATKHODJAEV, J. N
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Amsterdam Elsevier 01.09.1992
• Subjects: Bacterial Toxins - pharmacology; Biological and medical sciences; Biological membranes; Fundamental and applied biological sciences. Psychology; Hemolysin Proteins - pharmacology; Ion Channels - drug effects; Lipid Bilayers; Membrane physicochemistry; Molecular biophysics; Polyethylene Glycols - pharmacology; Size; Ion transport; Ionic channel; Bilayer; Toxin; Investigation method; Pore; Plasma membrane; Bacteria; Micrococcales; Micrococcaceae; Membrane channel; Staphylococcus aureus
• ISSN: 0920-8534

A new method of pore size determination is presented. The results of applying this simple method to ion channels formed by staphylococcal alpha-toxin and its N-terminal fragment as well as to cholera toxin channels are shown. The advantages and the difficulties of this method are discussed. It was found that (i) the mobility of ions in solutions depends only on the percentage of concentration of added non-electrolytes and practically not on their chemical nature (sugars or polyglycols) and molecular size; (ii) the proportional change of both ion channel conductance and bulk solution conductivity by low M. nonelectrolytes may be used as an indication of a diffusion mechanism of ion transport through channels; (iii) the slope of the dependence of the ion channel conductance on the bulk conductivity of solutions containing different concentrations of non-electrolyte is a good measure of channel permeability for non-electrolytes.