title: Membrane potential-dependent binding of polysialic acid to lipid monolayers and bilayers.
abstract: Polysialic acids are linear polysaccharides composed of sialic acid monomers. These polyanionic chains are usually membrane-bound, and are expressed on the surfaces of neural, tumor and neuroinvasive bacterial cells. We used toluidine blue spectroscopy, the Langmuir monolayer technique and fluorescence spectroscopy to study the effects of membrane surface potential and transmembrane potential on the binding of polysialic acids to lipid bilayers and monolayers. Polysialic acid free in solution was added to the bathing solution to assess the metachromatic shift in the absorption spectra of toluidine blue, the temperature dependence of the fluorescence anisotropy of DPH in liposomes, the limiting molecular area in lipid monolayers, and the fluorescence spectroscopy of oxonol V in liposomes. Our results show that both a positive surface potential and a positive transmembrane potential inside the vesicles can facilitate the binding of polysialic acid chains to model lipid membranes. These observations suggest that these membrane potentials can also affect the polysialic acid-mediated interaction between cells.
authors.affiliation: Department of Biotechnology and Molecular Biology, University of Opole, Kominka 6, 45-032, Opole, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Nowotarski
authors.forename: Karolina
authors.initials: K
authors.lastname: Sapoń
authors.forename: Monika
authors.initials: M
authors.lastname: Kowalska
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Janas
authors.forename: Teresa
authors.initials: T
authors.lastname: Janas
mesh_terms: D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D005454:Fluorescence Polarization; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism*; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism; D008564:Membrane Potentials; D012794:Sialic Acids / Q000378:metabolism*
chemical_list: D008051:Lipid Bilayers; D008081:Liposomes; D008563:Membrane Lipids; D012794:Sialic Acids; C021319:polysialic acid