title: Membrane-Sugar Interactions Probed by Pulsed Electron Paramagnetic Resonance of Spin Labels.
abstract: Sugars can stabilize biological systems under extreme desiccation and freezing conditions. Hypothetical molecular mechanisms suggest that the stabilization effect may be determined either by specific interactions of sugars with biological molecules or by the influence of sugars on the solvating shell of the biomolecule. To explore membrane-sugar interactions, we applied electron spin echo envelope modulation (ESEEM) spectroscopy, a pulsed version of electron paramagnetic resonance (EPR), to phospholipid bilayers with spin-labeled lipids added and solvated by aqueous deuterated sucrose and trehalose solutions. The phospholipids were 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). The spin-labeled lipids were 1,2-dipalmitoyl-sn-glycero-3-phospho(TEMPO)choline (T-PCSL), with spin-label TEMPO at the lipid polar headgroup. The deuterium ESEEM amplitude was calibrated using known concentrations of glassy deuterated sugar solvents. The data obtained indicated that the sugar concentration near the membrane surface obeyed a simple Langmuir model of monolayer adsorption, which assumes direct sugar-molecule bonding to the bilayer surface.
authors.affiliation: †Zavoisky Physical-Technical Institute, Russian Academy of Sciences, Kazan 420029, Russia.
authors.forename: Konstantin B
authors.initials: KB
authors.lastname: Konov
authors.affiliation: ‡Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia.|§Novosibirsk State University, Novosibirsk, 630090, Russia.
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Leonov
authors.affiliation: ‡Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia.|§Novosibirsk State University, Novosibirsk, 630090, Russia.
authors.forename: Nikolay P
authors.initials: NP
authors.lastname: Isaev
authors.affiliation: ‡Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia.|§Novosibirsk State University, Novosibirsk, 630090, Russia.
authors.forename: Kirill Yu
authors.initials: KY
authors.lastname: Fedotov
authors.affiliation: †Zavoisky Physical-Technical Institute, Russian Academy of Sciences, Kazan 420029, Russia.
authors.forename: Violeta K
authors.initials: VK
authors.lastname: Voronkova
authors.affiliation: ‡Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia.|§Novosibirsk State University, Novosibirsk, 630090, Russia.
authors.forename: Sergei A
authors.initials: SA
authors.lastname: Dzuba