title: CyanoP is Involved in the Early Steps of Photosystem II Assembly in the Cyanobacterium Synechocystis sp. PCC 6803.
abstract: Although the PSII complex is highly conserved in cyanobacteria and chloroplasts, the PsbU and PsbV subunits stabilizing the oxygen-evolving Mn4CaO5 cluster in cyanobacteria are absent in chloroplasts and have been replaced by the PsbP and PsbQ subunits. There is, however, a distant cyanobacterial homolog of PsbP, termed CyanoP, of unknown function. Here we show that CyanoP plays a role in the early stages of PSII biogenesis in Synechocystis sp. PCC 6803. CyanoP is present in the PSII reaction center assembly complex (RCII) lacking both the CP47 and CP43 modules and binds to the smaller D2 module. A small amount of larger PSII core complexes co-purifying with FLAG-tagged CyanoP indicates that CyanoP can accompany PSII on most of its assembly pathway. A role in biogenesis is supported by the accumulation of unassembled D1 precursor and impaired formation of RCII in a mutant lacking CyanoP. Interestingly, the pull-down preparations of CyanoP-FLAG from a strain lacking CP47 also contained PsbO, indicating engagement of this protein with PSII at a much earlier stage in assembly than previously assumed.
authors.affiliation: Institute of Microbiology, Center Algatech, Opatovický mlýn, 37981 Třeboň, Czech Republic Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Knoppová
authors.affiliation: Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Yu
authors.affiliation: Institute of Microbiology, Center Algatech, Opatovický mlýn, 37981 Třeboň, Czech Republic Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic.
authors.forename: Peter
authors.initials: P
authors.lastname: Konik
authors.affiliation: Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Nixon
authors.affiliation: Institute of Microbiology, Center Algatech, Opatovický mlýn, 37981 Třeboň, Czech Republic komenda@alga.cz.
authors.forename: Josef
authors.initials: J
authors.lastname: Komenda
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D045332:Photosystem II Protein Complex; D011994:Recombinant Proteins; C083100:photosystem II, chlorophyll binding protein, CP-43; C422369:photosystem II, psbA subunit
keywords: CyanoP; Cyanobacteria; Photosynthesis; Photosystem II; PsbP; Synechocystis