title: The formation of an inverted hexagonal phase from thylakoid membranes upon heating.
abstract: Barley thylakoid membranes were studied with FTIR and EPR spectroscopy. Thylakoids were exposed to elevated temperatures in order to induce structural changes. As temperatures increased through physiological to even higher levels, no features changed, but upon heating to above 45 degrees C, the fraction of lipid acyl chain segments with gauche-type vibration increased, accompanied by a sharp drop in the membranous spin probe component. These apparently conflicting observations in fact concur with the formation of an inverted hexagonal (H(II)) phase, supporting its putative role in protecting the photosynthetic machinery in thylakoid membranes against thermally-induced disassembly.
authors.affiliation: Inst. Biophys., Biological Research Centre Szeged, P.O. Box 521, 6701 Szeged, Hungary.
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Kóta
authors.forename: Balázs
authors.initials: B
authors.lastname: Szalontai
authors.forename: Magdolna
authors.initials: M
authors.lastname: Droppa
authors.forename: Gábor
authors.initials: G
authors.lastname: Hotváth
authors.forename: Tibor
authors.initials: T
authors.lastname: Páli
mesh_terms: D003497:Cyclic N-Oxides / Q000737:chemistry; D004075:Diglycerides / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D038983:Galactolipids; D006017:Glycolipids / Q000737:chemistry; D001467:Hordeum / Q000737:chemistry*; D006358:Hot Temperature; D017550:Spectroscopy, Fourier Transform Infrared; D013113:Spin Labels; D020524:Thylakoids / Q000737:chemistry*
chemical_list: D003497:Cyclic N-Oxides; D004075:Diglycerides; D038983:Galactolipids; D006017:Glycolipids; D013113:Spin Labels; C009909:monogalactosyldiacylglycerol; C001803:tempol