title: Relation between ionic channel conductance and conductivity of media containing different nonelectrolytes. A novel method of pore size determination.
abstract: The effects of nonelectrolytes on conductivity and viscosity of KCl solutions as well as on ion channel conductance were studied. Mobility of ions in solutions were found to solely depend on percent concentration (w/w) of the nonelectrolytes added and to be effectively independent on their chemical nature (sugars or polyglycols) and molecular size. Proportional changes in both the ion channel conductance and the conductivity of bulk solution induced by low m. w. nonelectrolytes may be used as a criterion of diffusion mechanism of ion transport through channels. The slope of the dependence of ion channel conductance on conductivity of bulk solution containing different concentrations of nonelectrolytes is a good measure of channel permeability for nonelectrolyte. A new method of pore size determination is introduced. Results of practical application of this simple method to three types of ion channels (formed by alpha-latrotoxin, staphylococcal alpha-toxin and its N-terminal fragment) are shown. The advantages and disadvantages of the method are discussed.
authors.affiliation: Institute of Physiology and Biophysics, Academy of Sciences, Tashkent, Uzbekistan.
authors.forename: R Z
authors.initials: RZ
authors.lastname: Sabirov
authors.forename: O V
authors.initials: OV
authors.lastname: Krasilnikov
authors.forename: V I
authors.initials: VI
authors.lastname: Ternovsky
authors.forename: P G
authors.initials: PG
authors.lastname: Merzliak
mesh_terms: D001427:Bacterial Toxins / Q000378:metabolism; D055592:Biophysical Phenomena; D001703:Biophysics; D004553:Electric Conductivity; D006460:Hemolysin Proteins / Q000378:metabolism; D066298:In Vitro Techniques; D007473:Ion Channels / Q000378:metabolism*; D017136:Ion Transport; D011108:Polymers; D011189:Potassium Chloride; D012996:Solutions; D013111:Spider Venoms / Q000378:metabolism; D013211:Staphylococcus aureus; D014783:Viscosity; D014867:Water
chemical_list: D001427:Bacterial Toxins; D006460:Hemolysin Proteins; D007473:Ion Channels; D011108:Polymers; D012996:Solutions; D013111:Spider Venoms; C021091:staphylococcal alpha-toxin; D014867:Water; C020763:alpha-latrotoxin; D011189:Potassium Chloride