title: Biochemical and Spectroscopic Characterization of Highly Stable Photosystem II Supercomplexes from Arabidopsis.
abstract: Photosystem II (PSII) is a large membrane supercomplex involved in the first step of oxygenic photosynthesis. It is organized as a dimer, with each monomer consisting of more than 20 subunits as well as several cofactors, including chlorophyll and carotenoid pigments, lipids, and ions. The isolation of stable and homogeneous PSII supercomplexes from plants has been a hindrance for their deep structural and functional characterization. In recent years, purification of complexes with different antenna sizes was achieved with mild detergent solubilization of photosynthetic membranes and fractionation on a sucrose gradient, but these preparations were only stable in the cold for a few hours. In this work, we present an improved protocol to obtain plant PSII supercomplexes that are stable for several hours/days at a wide range of temperatures and can be concentrated without degradation. Biochemical and spectroscopic properties of the purified PSII are presented, as well as a study of the complex solubility in the presence of salts. We also tested the impact of a large panel of detergents on PSII stability and found that very few are able to maintain the integrity of PSII. Such new PSII preparation opens the possibility of performing experiments that require room temperature conditions and/or high protein concentrations, and thus it will allow more detailed investigations into the structure and molecular mechanisms that underlie plant PSII function.
authors.affiliation: From the Aix Marseille Université, CEA, CNRS, BIAM, Laboratoire de Génétique et Biophysique des Plantes, Marseille 13009, France and.
authors.forename: Aurelie
authors.initials: A
authors.lastname: Crepin
authors.affiliation: the Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Santabarbara
authors.affiliation: From the Aix Marseille Université, CEA, CNRS, BIAM, Laboratoire de Génétique et Biophysique des Plantes, Marseille 13009, France and stefano.caffarri@univ-amu.fr.
authors.forename: Stefano
authors.initials: S
authors.lastname: Caffarri
mesh_terms: D017360:Arabidopsis / Q000201:enzymology*; D003902:Detergents / Q000737:chemistry*; D004795:Enzyme Stability; D007425:Intracellular Membranes / Q000737:chemistry*; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D003902:Detergents; D045332:Photosystem II Protein Complex
keywords: light-harvesting complex (antenna complex); photosynthesis; photosynthetic pigment; photosystem II; protein complex