title: Membrane crystals of plant light-harvesting complex II disassemble reversibly in light.
abstract: Using the mass-measuring capability of scanning transmission electron microscopy, we demonstrate that membrane crystals of the main light-harvesting complex of plants possess the ability to undergo light-induced dark-reversible disassociations, independently of the photochemical apparatus. This is the first direct visualization of light-driven reversible reorganizations in an isolated photosynthetic antenna. These reorganizations, identified earlier by circular dichroism (CD), can be accounted for by a biological thermo-optic transition: structural changes are induced by fast heat transients and thermal instabilities near the dissipation, and self-association of the complexes in the lipid matrix. A comparable process in native membranes is indicated by earlier findings of essentially identical kinetics, and intensity and temperature dependences of the ΔCD in granal thylakoids.
authors.affiliation: Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Hind
authors.affiliation: Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Wall
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, PO Box 521, H-6701, Hungary.
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Várkonyi
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, PO Box 521, H-6701, Hungary.
authors.forename: Anita
authors.initials: A
authors.lastname: Istokovics
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, PO Box 521, H-6701, Hungary.
authors.forename: Petar H
authors.initials: PH
authors.lastname: Lambrev
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, PO Box 521, H-6701, Hungary garab.gyozo@brc.mta.hu.
authors.forename: Győző
authors.initials: G
authors.lastname: Garab
mesh_terms: D000222:Adaptation, Physiological; D002412:Cations / Q000378:metabolism; D002942:Circular Dichroism; D003624:Darkness; D006358:Hot Temperature; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000648:ultrastructure; D008274:Magnesium / Q000378:metabolism; D008563:Membrane Lipids; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D018532:Pisum sativum / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000648:ultrastructure; D018515:Plant Leaves / Q000737:chemistry / Q000528:radiation effects / Q000648:ultrastructure; D020524:Thylakoids / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D002412:Cations; D045342:Light-Harvesting Protein Complexes; D008563:Membrane Lipids; D045332:Photosystem II Protein Complex; D008274:Magnesium
keywords: Granal thylakoid membranes; LHCII; Light-induced reorganizations; Lipid–protein interactions; Membrane crystal; Thermo-optic effect