help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Goudet, C.
Right arrow Articles by Thibaud, J.-B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Goudet, C.
Right arrow Articles by Thibaud, J.-B.

Biophys J, December 1999, p. 3052-3059, Vol. 77, No. 6

Cluster Organization and Pore Structure of Ion Channels Formed by Beticolin 3, a Nonpeptidic Fungal Toxin

Cyril Goudet,* Jean-Pierre Benitah,* Marie-Louise Milat,# Hervé Sentenac,* and Jean-Baptiste Thibaud*

 *Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, CNRS URA 2133/ENSA-M/INRA/UM2, 34060 Montpellier 1, and  #Laboratoire de Phytopharmacie et Biochimie des Interactions Cellulaires, UA 692 INRA/Université de Bourgogne, BV 1540, 21034 Dijon, France

Beticolin 3 (B3) belongs to a family of nonpeptidic phytotoxins produced by the fungus Cercospora beticola, which present a broad spectrum of cytotoxic effects. We report here that, at cytotoxic concentration (10 µM), B3 formed voltage-independent, weakly selective ion channels with multiple conductance levels in planar lipid bilayers. In symmetrical standard solutions, conductance values of the first levels were, respectively, 16 ± 1 pS, 32 ± 2 pS, and 57 ± 2 pS (n = 4) and so on, any conductance level being roughly twice the lower one. Whether a cluster organization of elementary channels or different channel structures underlies this particular property was addressed by investigating the ionic selectivity and the pore size corresponding to the first three conductance levels. Both selectivity and pore size were found to be almost independent of the conductance level. This indicated that multiple conductance behavior resulted from a cluster organization of "B3 elementary channels." According to the estimated pore size and analyses of x-ray diffraction of B3 microcrystals, a structural model for "B3 elementary channels" is proposed. The ability to form channels is likely to be involved in the biological activity of beticolins.

Biophys J, December 1999, p. 3052-3059, Vol. 77, No. 6
© 1999 by the Biophysical Society   0006-3495/99/12/3052/08  $2.00




HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1999 by the Biophysical Society.