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Rengstl B.,Molekulare Pflanzenwissenschaften | Knoppova J.,University of South Bohemia | Knoppova J.,Academy of Sciences of the Czech Republic | Komenda J.,University of South Bohemia | And 2 more authors.
Planta | Year: 2013

The de novo assembly of photosystem II (PSII) depends on a variety of assisting factors. We have previously shown that two of them, namely, YCF48 and Sll0933, mutually interact and form a complex (Rengstl et al. in J Biol Chem 286:21944-21951, 2011). To gain further insights into the importance of the YCF48/Sll0933 interaction, an ycf48-sll0933- double mutant was constructed and its phenotype was compared with the single mutants' phenotypes. Analysis of fluorescence spectra and oxygen evolution revealed high-light sensitivity not only for YCF48 deficient strains but also for sll0933-, which, in addition, showed reduced synthesis and accumulation of newly synthesized CP43 and CP47 proteins in pulse-labeling experiments. In general, the phenotypic characteristics of ycf48-sll0933- were dominated by the effect of the ycf48 deletion and additional inactivation of the sll0933 gene showed only negligible additional impairments with regard to growth, absorption spectra and accumulation of PSII-related proteins and assembly complexes. In yeast split-ubiquitin analyses, the interaction between YCF48 and Sll0933 was confirmed and, furthermore, support for direct binding of Sll0933 to CP43 and CP47 was obtained. Our data provide important new information which further refines our knowledge about the PSII assembly process and role of accessory protein factors within it. © 2012 Springer-Verlag. Source

Dorn K.V.,Albert Ludwigs University of Freiburg | Willmund F.,Albert Ludwigs University of Freiburg | Schwarz C.,Molekulare Pflanzenwissenschaften | Henselmann C.,Albert Ludwigs University of Freiburg | And 8 more authors.
Biochemical Journal | Year: 2010

In the present study we report on the identification and characterization of three novel chloroplast-targeted DnaJ-like proteins CDJ3-5, which in addition to their J-domains contain bacterial-type ferredoxin domains. In sequence databases we could identify homologues of CDJ3-5 in green algae, moss and higher plants, but not in cyanobacteria. Phylogenetic analyses allowed us to distinguish two clades containing CDJ3/4 and CDJ5 that must have diverged early in the ancestor of the 'green lineage' and have further diversified later on. Molecular and biochemical analysis of CDJ3 and CDJ4 from Chlamydomonas reinhardtii revealed that both proteins are weakly expressed and appear to be localized to the stroma and to thylakoid membranes respectively. The low transcript levels of the CDJ3 and CDJ4 genes declined even further in the initial phase of heat shock, but CDJ3 transcript levels strongly increased after a dark-to-light shift. Accordingly, the Arabidopsis orthologue of CDJ5 was also found to be light-inducible and to be under strong circadian control. CDJ3 and CDJ4 proteins could both be expressed in Escherichia coli and had redox-active Fe-S clusters. In vitro cross-linking studies demonstrated that CDJ3 and CDJ4 interact with chloroplast ATP-bound HSP70B (heat-shock protein 70B), presumably as dimers, and immunoprecipitation studies showed that CDJ3/4 were also in a complex with HSP70B in Chlamydomonas cell extracts. Finally, CDJ3 was found in complexes with apparent molecular masses of approx. 550-2800 kDa, which appeared to contain RNA. We speculate that the CDJ3-5 proteins might represent redox switches that act by recruiting HSP70B for the reorganization of regulatory protein complexes. © The Authors. Source

Heinz S.,Molekulare Pflanzenwissenschaften | Liauw P.,Ruhr University Bochum | Nickelsen J.,Molekulare Pflanzenwissenschaften | Nowaczyk M.,Ruhr University Bochum
Biochimica et Biophysica Acta - Bioenergetics | Year: 2016

Photosystem II (PSII), a large multisubunit membrane protein complex found in the thylakoid membranes of cyanobacteria, algae and plants, catalyzes light-driven oxygen evolution from water and reduction of plastoquinone. Biogenesis of PSII requires coordinated assembly of at least 20 protein subunits, as well as incorporation of various organic and inorganic cofactors. The stepwise assembly process is facilitated by numerous protein factors that have been identified in recent years. Further analysis of this process requires the development or refinement of specific methods for the identification of novel assembly factors and, in particular, elucidation of the unique role of each. Here we summarize current knowledge of PSII biogenesis in cyanobacteria, focusing primarily on the impact of methodological advances and innovations. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Conrad Mullineaux. © 2015 Elsevier B.V. All rights reserved. Source

Rast A.,Molekulare Pflanzenwissenschaften | Heinz S.,Molekulare Pflanzenwissenschaften | Nickelsen J.,Molekulare Pflanzenwissenschaften
Biochimica et biophysica acta | Year: 2015

Thylakoids mediate photosynthetic electron transfer and represent one of the most elaborate energy-transducing membrane systems. Despite our detailed knowledge of its structure and function, much remains to be learned about how the machinery is put together. The concerted synthesis and assembly of lipids, proteins and low-molecular-weight cofactors like pigments and transition metal ions require a high level of spatiotemporal coordination. While increasing numbers of assembly factors are being functionally characterized, the principles that govern how thylakoid membrane maturation is organized in space are just starting to emerge. In both cyanobacteria and chloroplasts, distinct production lines for the fabrication of photosynthetic complexes, in particular photosystem II, have been identified. This article is part of a Special Issue entitled: Chloroplast Biogenesis. Copyright © 2015 Elsevier B.V. All rights reserved. Source

Nickelsen J.,Molekulare Pflanzenwissenschaften | Rengstl B.,Molekulare Pflanzenwissenschaften | Stengel A.,Molekulare Pflanzenwissenschaften | Schottkowski M.,Molekulare Pflanzenwissenschaften | And 2 more authors.
FEMS Microbiology Letters | Year: 2011

Current molecular analyses suggest that initial steps of the biogenesis of cyanobacterial photosystems progress in a membrane subfraction representing a biosynthetic center with contact to both plasma and thylakoid membranes. This special membrane fraction is defined by the presence of the photosystem II assembly factor PratA. The proposed model suggests that both biogenesis of protein complexes and insertion of chlorophyll molecules into the photosystems occur in this intermediate membrane system. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved. Source

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