The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
Gene Review

psaI  -  photosystem I subunit VIII

Arabidopsis thaliana

Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

Disease relevance of psaI

  • The psbO gene of cyanobacteria, green algae and higher plants encodes the precursor of the 33 kDa manganese-stabilizing protein (MSP), a water-soluble subunit of photosystem II (PSII) [1].

High impact information on psaI

  • Photosystem II (PSII) is a key component of photosynthesis, the process of converting sunlight into the chemical energy of life [2].
  • When PSII is favoured (state 2), the redox conditions in the thylakoids change and result in activation of a protein kinase [3].
  • However, there was a major change in the macroorganization of PSII within these membranes; electron microscopy and image analysis revealed the complete absence of the C(2)S(2)M(2) light-harvesting complex II (LHCII)/PSII supercomplex predominant in wild-type plants [4].
  • To gain insight into the processes involved in photosystem II (PSII) biogenesis and maintenance, we characterized the low psii accumulation1 (lpa1) mutant of Arabidopsis thaliana, which generally accumulates lower than wild-type levels of the PSII complex [5].
  • We identified two such mechanisms: nonphotochemical energy dissipation (NPQ) in photosystem II (PSII) and synthesis of zeaxanthin [6].

Biological context of psaI

  • PsbH and PsbB are essential requirements for PSII assembly in photosynthetic eukaryotes, and their absence in hcf107 is consistent with the PSII-less mutant phenotype [7].
  • Using light sources that predominantly excite either photosystem I (PSI) or photosystem II (PSII), we modulated photosynthetic electron transport in tobacco, Arabidopsis, and Lemna sprouts [8].
  • This rapid process is referred to as a state transition and has been correlated with the phosphorylation and migration of the light-harvesting complex protein (LHCP) between PSII and PSI [9].
  • While PSII photoinhibition was similar in wild type and lut2 npq2 exposed to high light at low temperature, the double mutant was much more resistant to photooxidative stress and lipid peroxidation than the wild type [10].
  • When the wild type and lcd1-1 are exposed to short-term high-light stress, leaves do not bleach in lcd1-1 and potential activities of photosystems I (PSI) and II (PSII) decrease to a similar extent in both the genotypes, indicating that the photosynthetic apparatus is not affected by lcd1-1 mutation [11].

Anatomical context of psaI

  • The low protective efficiency of NPQ supports the conclusion that the Chl antenna of PSII is not the only photoreceptor of photoinhibition [12].

Associations of psaI with chemical compounds

  • We conclude that, in cooperation with the xanthophyll cycle, vitamin E fulfills at least two different functions in chloroplasts at the two major sites of singlet oxygen production: preserving PSII from photoinactivation and protecting membrane lipids from photooxidation [6].
  • However, a sucrose gradient separation of briefly solubilized thylakoid membranes revealed that no dimeric PSII supracomplex could be detected in the transgenic plants lacking the PsbW protein [13].
  • We propose that these effects result in an increased population of reduced primary electron-accepting quinone in PSII, facilitating non-radiative P680(+)Q(A)(-) radical pair recombination [14].
  • We found that changes in phenol metabolism result in altered rates of PSII reaction center heterodimer degradation under mixtures of photosynthetically active radiation and UV-B [15].
  • These results suggested that a deficiency of phylloquinone in PSI caused the abolishment of PSI and a partial defect of PSII due to a significant decrease of plastoquinone, but did not influence the ultrastructure of the chloroplasts in young leaves [16].

Analytical, diagnostic and therapeutic context of psaI


  1. Reconstitution of the spinach oxygen-evolving complex with recombinant Arabidopsis manganese-stabilizing protein. Betts, S.D., Hachigian, T.M., Pichersky, E., Yocum, C.F. Plant Mol. Biol. (1994) [Pubmed]
  2. Plants lacking the main light-harvesting complex retain photosystem II macro-organization. Ruban, A.V., Wentworth, M., Yakushevska, A.E., Andersson, J., Lee, P.J., Keegstra, W., Dekker, J.P., Boekema, E.J., Jansson, S., Horton, P. Nature (2003) [Pubmed]
  3. The PSI-H subunit of photosystem I is essential for state transitions in plant photosynthesis. Lunde, C., Jensen, P.E., Haldrup, A., Knoetzel, J., Scheller, H.V. Nature (2000) [Pubmed]
  4. Lack of the light-harvesting complex CP24 affects the structure and function of the grana membranes of higher plant chloroplasts. Kovács, L., Damkjaer, J., Kereïche, S., Ilioaia, C., Ruban, A.V., Boekema, E.J., Jansson, S., Horton, P. Plant Cell (2006) [Pubmed]
  5. LOW PSII ACCUMULATION1 is involved in efficient assembly of photosystem II in Arabidopsis thaliana. Peng, L., Ma, J., Chi, W., Guo, J., Zhu, S., Lu, Q., Lu, C., Zhang, L. Plant Cell (2006) [Pubmed]
  6. Vitamin E protects against photoinhibition and photooxidative stress in Arabidopsis thaliana. Havaux, M., Eymery, F., Porfirova, S., Rey, P., Dörmann, P. Plant Cell (2005) [Pubmed]
  7. The nucleus-encoded HCF107 gene of Arabidopsis provides a link between intercistronic RNA processing and the accumulation of translation-competent psbH transcripts in chloroplasts. Felder, S., Meierhoff, K., Sane, A.P., Meurer, J., Driemel, C., Plücken, H., Klaff, P., Stein, B., Bechtold, N., Westhoff, P. Plant Cell (2001) [Pubmed]
  8. Photosynthetic electron transport determines nitrate reductase gene expression and activity in higher plants. Sherameti, I., Sopory, S.K., Trebicka, A., Pfannschmidt, T., Oelmuller, R. J. Biol. Chem. (2002) [Pubmed]
  9. Disruption of thylakoid-associated kinase 1 leads to alteration of light harvesting in Arabidopsis. Snyders, S., Kohorn, B.D. J. Biol. Chem. (2001) [Pubmed]
  10. The effect of zeaxanthin as the only xanthophyll on the structure and function of the photosynthetic apparatus in Arabidopsis thaliana. Havaux, M., Dall'Osto, L., Cuiné, S., Giuliano, G., Bassi, R. J. Biol. Chem. (2004) [Pubmed]
  11. The lower cell density of leaf parenchyma in the Arabidopsis thaliana mutant lcd1-1 is associated with increased sensitivity to ozone and virulent Pseudomonas syringae. Barth, C., Conklin, P.L. Plant J. (2003) [Pubmed]
  12. Action Spectrum of Photoinhibition in Leaves of Wild Type and npq1-2 and npq4-1 Mutants of Arabidopsis thaliana. Sarvikas, P., Hakala, M., Pätsikkä, E., Tyystjärvi, T., Tyystjärvi, E. Plant Cell Physiol. (2006) [Pubmed]
  13. The low molecular mass PsbW protein is involved in the stabilization of the dimeric photosystem II complex in Arabidopsis thaliana. Shi, L.X., Lorković, Z.J., Oelmuller, R., Schroder, W.P. J. Biol. Chem. (2000) [Pubmed]
  14. Changes in the redox potential of primary and secondary electron-accepting quinones in photosystem II confer increased resistance to photoinhibition in low-temperature-acclimated Arabidopsis. Sane, P.V., Ivanov, A.G., Hurry, V., Huner, N.P., Oquist, G. Plant Physiol. (2003) [Pubmed]
  15. Ultraviolet-B radiation impacts light-mediated turnover of the photosystem II reaction center heterodimer in Arabidopsis mutants altered in phenolic metabolism. Booij-James, I.S., Dube, S.K., Jansen, M.A., Edelman, M., Mattoo, A.K. Plant Physiol. (2000) [Pubmed]
  16. Inactivation and deficiency of core proteins of photosystems I and II caused by genetical phylloquinone and plastoquinone deficiency but retained lamellar structure in a T-DNA mutant of Arabidopsis. Shimada, H., Ohno, R., Shibata, M., Ikegami, I., Onai, K., Ohto, M.A., Takamiya, K. Plant J. (2005) [Pubmed]
  17. A redox-active FKBP-type immunophilin functions in accumulation of the photosystem II supercomplex in Arabidopsis thaliana. Lima, A., Lima, S., Wong, J.H., Phillips, R.S., Buchanan, B.B., Luan, S. Proc. Natl. Acad. Sci. U.S.A. (2006) [Pubmed]
  18. The structure of photosystem II in Arabidopsis: localization of the CP26 and CP29 antenna complexes. Yakushevska, A.E., Keegstra, W., Boekema, E.J., Dekker, J.P., Andersson, J., Jansson, S., Ruban, A.V., Horton, P. Biochemistry (2003) [Pubmed]
  19. Quantitative analysis of the effects of intrathylakoid pH and xanthophyll cycle pigments on chlorophyll a fluorescence lifetime distributions and intensity in thylakoids. Gilmore, A.M., Shinkarev, V.P., Hazlett, T.L., Govindjee, G. Biochemistry (1998) [Pubmed]
  20. The HCF136 protein is essential for assembly of the photosystem II reaction center in Arabidopsis thaliana. Plücken, H., Müller, B., Grohmann, D., Westhoff, P., Eichacker, L.A. FEBS Lett. (2002) [Pubmed]
  21. Photosynthetic genes are differentially transcribed during the dehydration-rehydration cycle in the resurrection plant, Xerophyta humilis. Collett, H., Butowt, R., Smith, J., Farrant, J., Illing, N. J. Exp. Bot. (2003) [Pubmed]
WikiGenes - Universities