title: Two types of syringomycin E channels in sphingomyelin-containing bilayers.
abstract: The influence of dipole modifiers on the characteristics of single syringomycin E (SRE) channels in bilayers comprising DOPS, DOPE, sphingolipids (sphingomyelin, N-stearoyl-phytosphingosine or N-stearoyl-sphinganine) and sterols (cholesterol or ergosterol) was studied. The effects of dipole modifiers on SRE channel amplitudes were dependent upon the sphingolipid type and were not affected by the membrane sterol content. A decrease in the dipole potential of phytosphingosine- and sphinganine-containing bilayers, which was induced by the adsorption of phloretin, led to a reduction in conductance; however, an increase in this potential, which occurred upon the addition of RH 421, led to an enhancement in the conductance of SRE channels. Two channel populations, one of which is sensitive while the other is insensitive to modifiers, were found in sphingomyelin-containing bilayers. This indicates that SRE channels are distributed in lipid domains with different dipole potentials.
authors.affiliation: Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg, Russia, 194064. ssefimova@mail.ru.
authors.forename: Svetlana S
authors.initials: SS
authors.lastname: Efimova
authors.affiliation: Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg, Russia, 194064.
authors.forename: Anastasiia A
authors.initials: AA
authors.lastname: Zakharova
authors.affiliation: Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg, Russia, 194064.
authors.forename: Ludmila V
authors.initials: LV
authors.lastname: Schagina
authors.affiliation: Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg, Russia, 194064.
authors.forename: Olga S
authors.initials: OS
authors.lastname: Ostroumova
mesh_terms: D002784:Cholesterol / Q000737:chemistry; D004875:Ergosterol / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000737:chemistry*; D013109:Sphingomyelins / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D010456:Peptides, Cyclic; D013109:Sphingomyelins; C105246:syringomycin E; D002784:Cholesterol; D004875:Ergosterol
keywords: Lipid phase separation; Membrane dipole potential; Planar lipid membranes; Single ion channels; Sphingolipids; Syringomycin E