title: One-step isolation and biochemical characterization of a highly active plant PSII monomeric core.
abstract: We describe a one-step detergent solubilization protocol for isolating a highly active form of Photosystem II (PSII) from Pisum sativum L. Detailed characterization of the preparation showed that the complex was a monomer having no light harvesting proteins attached. This core reaction centre complex had, however, a range of low molecular mass intrinsic proteins as well as the chlorophyll binding proteins CP43 and CP47 and the reaction centre proteins D1 and D2. Of particular note was the presence of a stoichiometric level of PsbW, a low molecular weight protein not present in PSII of cyanobacteria. Despite the high oxygen evolution rate, the core complex did not retain the PsbQ extrinsic protein although there was close to a full complement of PsbO and PsbR and partial level of PsbP. However, reconstitution of PsbP and PsbPQ was possible. The presence of PsbP in absence of LHCII and other chlorophyll a/b binding proteins confirms that LHCII proteins are not a strict requirement for the assembly of this extrinsic polypeptide to the PSII core in contrast with the conclusion of Caffarri et al. (2009).
authors.affiliation: Department of Materials Science and Chemical Engineering - BioSolar Lab, Politecnico di Torino, Viale T. Michel 5, 15121, Alessandria, Italy. cristina.pagliano@polito.it
authors.forename: Cristina
authors.initials: C
authors.lastname: Pagliano
authors.forename: Fabiana
authors.initials: F
authors.lastname: Chimirri
authors.forename: Guido
authors.initials: G
authors.lastname: Saracco
authors.forename: Francesco
authors.initials: F
authors.lastname: Marsano
authors.forename: James
authors.initials: J
authors.lastname: Barber
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D008565:Membrane Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D010100:Oxygen / Q000032:analysis / Q000378:metabolism; D018532:Pisum sativum / Q000737:chemistry* / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D021122:Protein Subunits / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053719:Tandem Mass Spectrometry; D013696:Temperature; D020524:Thylakoids / Q000737:chemistry* / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D021122:Protein Subunits; D010100:Oxygen