Advances in the Understanding of the Lifecycle of Photosystem II

Johnson, Virginia M.; Pakrasi, Himadri B.

doi:10.3390/microorganisms10050836

Cited by 23 publications

(13 citation statements)

References 151 publications

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“…PsbH is a subunit found in the PSII holocomplexes of all oxygenic phototrophs. It associates with PsbB early in PSII biogenesis, prior even to the association of PsbB with the PsbA and PsbD core subunits ( 29 , 30 ). In the PSII holocomplex, PsbH is needed to maintain the stability of the bicarbonate anion and therefore influences the Q A to Q B electron transfer rate ( 31 ).…”

Section: Resultsmentioning

confidence: 99%

Structure of a dimeric photosystem II complex from a cyanobacterium acclimated to far-red light

Gisriel

Shen

Flesher

et al. 2023

Journal of Biological Chemistry

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Section: Resultsmentioning

confidence: 99%

Structure of a dimeric photosystem II complex from a cyanobacterium acclimated to far-red light

Gisriel

Shen

Flesher

et al. 2023

Journal of Biological Chemistry

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“…Although we could not find water-access modalities to the Mn-center in our analyses, some reports from other groups demarcate several channels [93]. If this were in fact the case, how is it physically possible to restrict two specific water molecules at the active complex, simultaneously preventing the formation/release of DRS at/ from PS II [94]? This query would still remain inexplicable in the classical perspective, seeking more and more intangible apologetics of the classical view.…”

Section: Summationmentioning

confidence: 60%

Comprehensive Analyses of the Enhancement of Oxygenesis in Photosynthesis by Bicarbonate and Effects of Diverse Additives: Z-scheme Explanation versus Murburn Model

Manoj¹,

Bazhin²,

Parashar³

et al. 2023

Physiology

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The Z-scheme electron transport chain (ETC) explanation for photosynthesis starts with the serial/sequential transfer of electrons sourced from water molecules bound at Photosystem II via a deterministic array of redox centers (of various stationary/mobile proteins), before \"sinking\" via the reduction of NADP+ bound at flavin-enzyme reductase. Several research groups’ finding that additives (like bicarbonate) enhance the light reaction had divided the research community because it violated the Z-scheme. The untenable aspects of the Z-scheme perception were demonstrated earlier and a murburn bioenergetics (a stochastic/parallel paradigm of ion-radical equilibriums) model was proposed to explain photophosphorylation and Emerson effect. Herein, we further support the murburn model with accurate thermodynamic calculations, which show that the cost of one-electron abstraction from bicarbonate [491 kJ/mol] is lower than water [527 kJ/mol]. Further, copious thioredoxin enables the capture of photoactivated electrons in milieu, which aid in the reduction of nicotinamide nucleotides. The diffusible reactive species (DRS) generated in milieu sponsor phosphorylations and oxygenic reactions. With structural analysis of Photosystems and interacting molecules, we chart out the equations of reactions that explain the loss of labeled O-atom traces in delocalized oxygenesis. Thus, this essay discredits the Z-scheme and explains key outstanding observations in the field.

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“…These two subunits together bind three macromolecules that are fundamental for photosynthetic light reactions: the P680 reaction center, which transfers energy to water molecules, the Mn 4 CaO 5 cluster responsible for the splitting of water molecules and retrieval of electrons, and components of the primary electron transfer chain, such as plastoquinones Q A and Q B [61]. The PSII reaction center is completed by the subunit encoded by the PSBI gene and cytochrome b559, composed of subunits encoded by the PSBE and PSBF genes and a heme co-factor [62]. The PSBD gene is highly expressed in A. thaliana plants grown under both treatments, and H. incana plants grown under HL, while the PSBE gene is highly expressed only in H. incana plants grown under HL (Figures 4d, S9, S10).…”

Section: Resultsmentioning

confidence: 99%

Comparative transcriptomics of Hirschfeldia incana and relatives highlights differences in photosynthetic pathways

Garassino,

Luoni,

Cumerlato

et al. 2023

Preprint

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Photosynthesis is the only yield-related trait that has not yet been substantially improved by plant breeding. The limited results of previous attempts to increase yield via improvement of photosynthetic pathways suggest that more knowledge is still needed to achieve this goal. To learn more about the genetic and physiological basis of high photosynthetic light-use efficiency (LUE) at high irradiance, we studyHirschfeldia incana. Here, we compare the transcriptomic response to high light ofH. incanawith that of three other members of the Brassicaceae,Arabidopsis thaliana,Brassica rapa, andBrassica nigra, which have a lower photosynthetic LUE. First, we built a high-light, high-uniformity growing environment in a climate-controlled room. Plants grown in this system developed normally and showed no signs of stress during the whole growth period. Then we compared gene expression in low and high-light conditions across the four species, utilizing a panproteome to group homologous proteins efficiently. As expected, all species actively regulate genes related to the photosynthetic process. An in-depth analysis on the expression of genes involved in three key photosynthetic pathways revealed a general trend of lower gene expression in high-light conditions. However,H. incanadistinguishes itself from the other species through higher expression of certain genes in these pathways, either through constitutive higher expression, as forLHCB8, ordinary differential expression, as forPSBE, or cumulative higher expression obtained by simultaneous expression of multiple gene copies, as seen forLHCA6. These differentially expressed genes in photosynthetic pathways are interesting leads to further investigate the exact relationship between gene expression, protein abundance and turnover, and ultimately the LUE phenotype. In addition, we can also exclude thousands of genes from "explaining" the phenotype, because they do not show differential expression between both light conditions. Finally, we deliver a transcriptomic resource of plant species fully grown under, rather than briefly exposed to, a very high irradiance, supporting efforts to develop highly efficient photosynthesis in crop plants.

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Advances in the Understanding of the Lifecycle of Photosystem II

Cited by 23 publications

References 151 publications

Structure of a dimeric photosystem II complex from a cyanobacterium acclimated to far-red light

Structure of a dimeric photosystem II complex from a cyanobacterium acclimated to far-red light

Comprehensive Analyses of the Enhancement of Oxygenesis in Photosynthesis by Bicarbonate and Effects of Diverse Additives: Z-scheme Explanation versus Murburn Model

Comparative transcriptomics of Hirschfeldia incana and relatives highlights differences in photosynthetic pathways

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