A1 Refereed original research article in a scientific journal
Photoproduction of hydrogen by sulfur-deprived C reinhardtii mutants with impaired Photosystem II photochemical activity
Authors: Makarova VV, Kosourov S, Krendeleva TE, Semin BK, Kukarskikh GP, Rubin AB, Sayre RT, Ghirardi ML, Seibert M
Publisher: SPRINGER
Publication year: 2007
Journal: Photosynthesis Research
Journal name in source: PHOTOSYNTHESIS RESEARCH
Journal acronym: PHOTOSYNTH RES
Volume: 94
Issue: 1
First page : 79
Last page: 89
Number of pages: 11
ISSN: 0166-8595
DOI: https://doi.org/10.1007/s11120-007-9219-4
Abstract
Photoproduction of H-2 was examined in a series of sulfur-deprived Chlamydomonas reinhardtii D1-R323 mutants with progressively impaired PSII photochemical activity. In the R323H, R323D, and R323E D1 mutants, replacement of arginine affects photosystem II (PSII) function, as demonstrated by progressive decreases in O-2-evolving activity and loss of PSII photochemical activity. Significant changes in PSII activity were found when the arginine residue was replaced by negatively charged amino acid residues (R323D and R323E). However, the R323H (positively charged or neutral, depending on the ambient pH) mutant had minimal changes in PSII activity. The R323H, R323D, and R323E mutants and the pseudo-wild-type (pWt) with restored PSII function were used to study the effects of sulfur deprivation on H-2-production activity. All of these mutants exhibited significant changes in the normal parameters associated with the H-2-photoproduction process, such as a shorter aerobic phase, lower accumulation of starch, a prolonged anaerobic phase observed before the onset of H-2-production, a shorter duration of H-2-production, lower H-2 yields compared to the pWt control, and slightly higher production of dark fermentation products such as acetate and formate. The more compromised the PSII photochemical activity, the more dramatic was the effect of sulfur deprivation on the H-2-production process, which depends both on the presence of residual PSII activity and the amount of stored starch.
Photoproduction of H-2 was examined in a series of sulfur-deprived Chlamydomonas reinhardtii D1-R323 mutants with progressively impaired PSII photochemical activity. In the R323H, R323D, and R323E D1 mutants, replacement of arginine affects photosystem II (PSII) function, as demonstrated by progressive decreases in O-2-evolving activity and loss of PSII photochemical activity. Significant changes in PSII activity were found when the arginine residue was replaced by negatively charged amino acid residues (R323D and R323E). However, the R323H (positively charged or neutral, depending on the ambient pH) mutant had minimal changes in PSII activity. The R323H, R323D, and R323E mutants and the pseudo-wild-type (pWt) with restored PSII function were used to study the effects of sulfur deprivation on H-2-production activity. All of these mutants exhibited significant changes in the normal parameters associated with the H-2-photoproduction process, such as a shorter aerobic phase, lower accumulation of starch, a prolonged anaerobic phase observed before the onset of H-2-production, a shorter duration of H-2-production, lower H-2 yields compared to the pWt control, and slightly higher production of dark fermentation products such as acetate and formate. The more compromised the PSII photochemical activity, the more dramatic was the effect of sulfur deprivation on the H-2-production process, which depends both on the presence of residual PSII activity and the amount of stored starch.
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