Assembly of the water-oxidizing complex in photosystem II

Becker, Kristin; Cormann, Kai U.; Nowaczyk, Marc M.

doi:10.1016/j.jphotobiol.2011.02.005

Cited by 56 publications

(46 citation statements)

References 93 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the binding partner(s) of Psb27 in such PSII complex remain poorly defined. For example, it has been hypothesized that Psb27 binds to the lumenal area of CP47 (37,41) or CP43 (42). We are currently investigating the structural location of Psb27 in the PSII assembly intermediate complexes described in this report.…”

Section: Discussionmentioning

confidence: 92%

A Genetically Tagged Psb27 Protein Allows Purification of Two Consecutive Photosystem II (PSII) Assembly Intermediates in Synechocystis 6803, a Cyanobacterium

Liu

Roose²,

Cameron

et al. 2011

Journal of Biological Chemistry

View full text Add to dashboard Cite

Photosystem II (PSII) is a large membrane bound molecular machine that catalyzes light-driven oxygen evolution from water. PSII constantly undergoes assembly and disassembly because of the unavoidable damage that results from its normal photochemistry. Thus, under physiological conditions, in addition to the active PSII complexes, there are always PSII subpopulations incompetent of oxygen evolution, but are in the process of undergoing elaborate biogenesis and repair. These transient complexes are difficult to characterize because of their low abundance, structural heterogeneity, and thermodynamic instability. In this study, we show that a genetically tagged Psb27 protein allows for the biochemical purification of two monomeric PSII assembly intermediates, one with an unprocessed form of D1 (His27⌬ctpAPSII) and a second one with a mature form of D1 (His27PSII). Both forms were capable of light-induced charge separation, but unable to photooxidize water, largely because of the absence of a functional tetramanganese cluster. Unexpectedly, there was a significant amount of the extrinsic lumenal PsbO protein in the His27PSII, but not in the His27⌬ctpAPSII complex. In contrast, two other lumenal proteins, PsbU and PsbV, were absent in both of these PSII intermediate complexes. Additionally, the only cytoplasmic extrinsic protein, Psb28 was detected in His27PSII complex. Based on these data, we have presented a refined model of PSII biogenesis, illustrating an important role of Psb27 as a gate-keeper during the complex assembly process of the oxygen-evolving centers in PSII.Photosystem II (PSII) 3 is a large membrane protein complex found in the thylakoids membranes of cyanobacteria, algae, and higher plants. It catalyzes oxidation of water and reduction of plastoquinone (PQ). These activities are essential for the conversion of solar energy to the chemical energy used by the vast majority of life on earth and for the production of molecular oxygen.Recent structural studies have provided a detailed yet static view of PSII (1-3). Accordingly, a PSII monomer is comprised of 20 protein subunits, which form a proteinaceous scaffold holding two pheophytin a (Pheo), 35 chlorophyll a (Chla), one non-heme iron, two hemes (Cyt b 559 and Cyt c 550 ), three PQ, and 12 ␤-carotene (4, 5) molecules as cofactors. The light driven electron transfer reactions through the PSII complex requires precise positioning of all these cofactors and an inorganic (Mn 4 -Ca) cluster on lumenal side, the latter of which is also called water-oxidizing complex (WOC). However, the cost of water oxidation is high: photooxidative damage inevitably occurs to PSII, in which P680 ϩ , the strongest biological oxidant, is generated and finally leads to the splitting of water to molecular oxygen, protons, and electrons. Under physiological conditions, an elaborate and well-orchestrated repair process repairs such damages, so that PSII can function optimally.Because PSII is under constant repair and biogenesis, elucidation of the details of the PSII assembly p...

show abstract

Section: Discussionmentioning

confidence: 92%

A Genetically Tagged Psb27 Protein Allows Purification of Two Consecutive Photosystem II (PSII) Assembly Intermediates in Synechocystis 6803, a Cyanobacterium

Liu

Roose²,

Cameron

et al. 2011

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…However, blockage of the PSII activity by addition of DCMU did not affect the PSI rereduction kinetics, which strongly indicates that the PQ pool is not reduced by PSII in dark-grown cells, most likely due to a nonfunctional PSII donor side. Notably, assembly of the catalytically active tetramanganese cluster at the PSII donor side, the so-called photoactivation process, is light dependent (Becker et al, 2011), and the observed PSII complexes might represent a manganese-depleted, inactive PSII precursor form (Nixon et al, 2010;Nowaczyk et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

Thylakoid Membrane Maturation and PSII Activation Are Linked in Greening Synechocystis sp. PCC 6803 Cells

Barthel

Bernát

Seidel³

et al. 2013

Plant Physiology

View full text Add to dashboard Cite

Thylakoid membranes are typical and essential features of both chloroplasts and cyanobacteria. While they are crucial for phototrophic growth of cyanobacterial cells, biogenesis of thylakoid membranes is not well understood yet. Dark-grown Synechocystis sp. PCC 6803 cells contain only rudimentary thylakoid membranes but still a relatively high amount of phycobilisomes, inactive photosystem II and active photosystem I centers. After shifting dark-grown Synechocystis sp. PCC 6803 cells into the light, “greening” of Synechocystis sp. PCC 6803 cells, i.e. thylakoid membrane formation and recovery of photosynthetic electron transport reactions, was monitored. Complete restoration of a typical thylakoid membrane system was observed within 24 hours after an initial lag phase of 6 to 8 hours. Furthermore, activation of photosystem II complexes and restoration of a functional photosynthetic electron transport chain appears to be linked to the biogenesis of organized thylakoid membrane pairs.

show abstract

“…(vi) Protection and repair mechanisms that limit oxidative damage of the protein pocket and replace the protein scaffold every 30 min under full sunlight [39]. It is noted that the water splitting catalyst binds to the protein and assembles spontaneously from free Mn 2þ…”

Section: Key Design Features Of the Oxygen Evolving Complexmentioning

confidence: 99%

Artificial photosynthesis: understanding water splitting in nature

et al. 2015

View full text Add to dashboard Cite

One contribution of 11 to a theme issue 'Do we need a global project on artificial photosynthesis (solar fuels and chemicals)?'. In the context of a global artificial photosynthesis (GAP) project, we review our current work on nature's water splitting catalyst. In a recent report (Cox et al. 2014 Science 345, 804-808 (doi:10.1126/science.1254910)), we showed that the catalyst-a Mn 4 O 5 Ca cofactor-converts into an 'activated' form immediately prior to the O-O bond formation step. This activated state, which represents an all Mn IV complex, is similar to the structure observed by X-ray crystallography but requires the coordination of an additional water molecule. Such a structure locates two oxygens, both derived from water, in close proximity, which probably come together to form the product O 2 molecule. We speculate that formation of the activated catalyst state requires inherent structural flexibility. These features represent new design criteria for the development of biomimetic and bioinspired model systems for water splitting catalysts using first-row transition metals with the aim of delivering globally deployable artificial photosynthesis technologies.

show abstract

Assembly of the water-oxidizing complex in photosystem II

Cited by 56 publications

References 93 publications

A Genetically Tagged Psb27 Protein Allows Purification of Two Consecutive Photosystem II (PSII) Assembly Intermediates in Synechocystis 6803, a Cyanobacterium

A Genetically Tagged Psb27 Protein Allows Purification of Two Consecutive Photosystem II (PSII) Assembly Intermediates in Synechocystis 6803, a Cyanobacterium

Thylakoid Membrane Maturation and PSII Activation Are Linked in Greening Synechocystis sp. PCC 6803 Cells

Artificial photosynthesis: understanding water splitting in nature

Contact Info

Product

Resources

About