title: Isolation of Plant Photosystem II Complexes by Fractional Solubilization.
abstract: Photosystem II (PSII) occurs in different forms and supercomplexes in thylakoid membranes. Using a transplastomic strain of Nicotiana tabacum histidine tagged on the subunit PsbE, we have previously shown that a mild extraction protocol with β-dodecylmaltoside enriches PSII characteristic of lamellae and grana margins. Here, we characterize residual granal PSII that is not extracted by this first solubilization step. Using affinity purification, we demonstrate that this PSII fraction consists of PSII-LHCII mega- and supercomplexes, PSII dimers, and PSII monomers, which were separated by gel filtration and functionally characterized. Our findings represent an alternative demonstration of different PSII populations in thylakoid membranes, and they make it possible to prepare PSII-LHCII supercomplexes in high yield.
authors.affiliation: Laboratory of Structural Biology, Department of Molecular Biology, International Institute of Molecular and Cell Biology Warsaw, Poland.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Haniewicz
authors.affiliation: Laboratory of Photosynthesis and Photobiology, Department of Life and Environmental Sciences, University of Cagliari Cagliari, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Floris
authors.affiliation: Laboratory of Photosynthesis and Photobiology, Department of Life and Environmental Sciences, University of Cagliari Cagliari, Italy.
authors.forename: Domenica
authors.initials: D
authors.lastname: Farci
authors.affiliation: Proteomics Core Facility, European Molecular Biology Laboratory Heidelberg, Germany.
authors.forename: Joanna
authors.initials: J
authors.lastname: Kirkpatrick
authors.affiliation: Laboratory of Photosynthesis and Photobiology, Department of Life and Environmental Sciences, University of Cagliari Cagliari, Italy.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Loi
authors.affiliation: Laboratory of Plant Cell Physiology, Institute of Molecular Biosciences, Goethe-University Frankfurt Frankfurt am Main, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Büchel
authors.affiliation: Laboratory of Structural Biology, Department of Molecular Biology, International Institute of Molecular and Cell Biology Warsaw, Poland ; Department of Bioinformatics, Institute of Biochemistry and Biophysics Warsaw, Poland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Bochtler
authors.affiliation: Laboratory of Structural Biology, Department of Molecular Biology, International Institute of Molecular and Cell Biology Warsaw, Poland ; Laboratory of Photosynthesis and Photobiology, Department of Life and Environmental Sciences, University of Cagliari Cagliari, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Piano
keywords: Nicotiana tabacum; PSII-LHCII megacomplex; PSII-LHCII supercomplex; oligomeric state; photosystem II; thylakoid membranes