Scientific article
Open access

Photosystem I is Indispensable for Photoautotrophic Growth, CO2 Fixation, and H2 Photoproduction in Chlamydomonas reinhardtii

Published inJournal of Biological Chemistry, vol. 274, no. 15, p. 10466-10473
Publication date1999

Certain Chlamydomonas reinhardtiimutants deficient in photosystem I due to defects in psaAmRNA maturation have been reported to be capable of CO₂ fixation, H₂ photoevolution, and photoautotrophic growth (Greenbaum, E., Lee, J. W., Tevault, C. V., Blankinship, S. L., and Mets, L. J. (1995) Nature 376, 438–441 and Lee, J. W., Tevault, C. V., Owens, T. G.; Greenbaum, E. (1996) Science 273, 364–367). We have generated deletions of photosystem I core subunits in both wild type and these mutant strains and have analyzed their abilities to grow photoautotrophically, to fix CO₂, and to photoevolve O₂ or H₂ (using mass spectrometry) as well as their photosystem I content (using immunological and spectroscopic analyses). We find no instance of a strain that can perform photosynthesis in the absence of photosystem I. The F8 strain harbored a small amount of photosystem I, and it could fix CO₂ and grow slowly, but it lost these abilities after deletion of eitherpsaA or psaC; these activities could be restored to the F8-psaAΔ mutant by reintroduction ofpsaA. We observed limited O₂ photoevolution in mutants lacking photosystem I; use of ¹⁸O₂ indicated that this O₂ evolution is coupled to O₂ uptake (i.e.respiration) rather than CO₂ fixation or H₂ evolution. We conclude that the reported instances of CO₂ fixation, H₂ photoevolution, and photoautotrophic growth of photosystem I-deficient mutants result from the presence of unrecognized photosystem I.

  • Swiss National Science Foundation - 3100-050885.97
Citation (ISO format)
REDDING, Kevin et al. Photosystem I is Indispensable for Photoautotrophic Growth, CO<sub>2</sub> Fixation, and H<sub>2</sub> Photoproduction in <i>Chlamydomonas reinhardtii</i>. In: Journal of Biological Chemistry, 1999, vol. 274, n° 15, p. 10466–10473. doi: 10.1074/jbc.274.15.10466
Main files (1)
Article (Published version)
ISSN of the journal0021-9258

Technical informations

Creation01/08/2020 12:31:00 PM
First validation01/08/2020 12:31:00 PM
Update time03/15/2023 6:41:24 PM
Status update03/15/2023 6:41:23 PM
Last indexation08/30/2023 10:00:39 PM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack