title: Dark-adapted spinach thylakoid protein heterogeneity offers insights into the photosystem II repair cycle.
abstract: In higher plants, thylakoid membrane protein complexes show lateral heterogeneity in their distribution: photosystem (PS) II complexes are mostly located in grana stacks, whereas PSI and adenosine triphosphate (ATP) synthase are mostly found in the stroma-exposed thylakoids. However, recent research has revealed strong dynamics in distribution of photosystems and their light harvesting antenna along the thylakoid membrane. Here, the dark-adapted spinach (Spinacia oleracea L.) thylakoid network was mechanically fragmented and the composition of distinct PSII-related proteins in various thylakoid subdomains was analyzed in order to get more insights into the composition and localization of various PSII subcomplexes and auxiliary proteins during the PSII repair cycle. Most of the PSII subunits followed rather equal distribution with roughly 70% of the proteins located collectively in the grana thylakoids and grana margins; however, the low molecular mass subunits PsbW and PsbX as well as the PsbS proteins were found to be more exclusively located in grana thylakoids. The auxiliary proteins assisting in repair cycle of PSII were mostly located in stroma-exposed thylakoids, with the exception of THYLAKOID LUMEN PROTEIN OF 18.3 (TLP18.3), which was more evenly distributed between the grana and stroma thylakoids. The TL29 protein was present exclusively in grana thylakoids. Intriguingly, PROTON GRADIENT REGULATION5 (PGR5) was found to be distributed quite evenly between grana and stroma thylakoids, whereas PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE1 (PGRL1) was highly enriched in the stroma thylakoids and practically missing from the grana cores. This article is part of a special issue entitled: photosynthesis research for sustainability: keys to produce clean energy.
authors.affiliation: Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Marjaana
authors.initials: M
authors.lastname: Suorsa
authors.affiliation: Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Marjaana
authors.initials: M
authors.lastname: Rantala
authors.affiliation: Department of Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, SE-22100 Lund, Sweden.
authors.forename: Ravi
authors.initials: R
authors.lastname: Danielsson
authors.affiliation: Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Sari
authors.initials: S
authors.lastname: Järvi
authors.affiliation: Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Virpi
authors.initials: V
authors.lastname: Paakkarinen
authors.affiliation: Umeå Plant Science Center and Department of Chemistry, Linnaeus väg 10, University of Umeå, SE-901 87 Umeå, Sweden.
authors.forename: Wolfgang P
authors.initials: WP
authors.lastname: Schröder
authors.affiliation: Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, University of Uppsala, Box 523, SE-75120 Uppsala, Sweden.
authors.forename: Stenbjörn
authors.initials: S
authors.lastname: Styring
authors.affiliation: Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, University of Uppsala, Box 523, SE-75120 Uppsala, Sweden. Electronic address: fikret.mamedov@kemi.uu.se.
authors.forename: Fikret
authors.initials: F
authors.lastname: Mamedov
authors.affiliation: Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland. Electronic address: evaaro@utu.fi.
authors.forename: Eva-Mari
authors.initials: EM
authors.lastname: Aro
mesh_terms: D000222:Adaptation, Physiological; D003624:Darkness; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D010940:Plant Proteins / Q000032:analysis*; D018724:Spinacia oleracea / Q000737:chemistry*; D020524:Thylakoids / Q000737:chemistry*
chemical_list: D045332:Photosystem II Protein Complex; D010940:Plant Proteins
keywords: PGR5; PGRL1; Photosystem II; PsbS; PsbW; PsbX