NADP-Malate Dehydrogenase from Unicellular Green Alga Chlamydomonas reinhardtii. A First Step toward Redox Regulation?
In: Plant Physiology, Jg. 137 (2005-02-01), Heft 2, S. 514-521
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Zugriff:
The determinants of the thioredoxin (TRX)-dependent redox regulation of the chloroplastic NADP-malate dehydrogenase (NADP-MDH) from the eukaryotic green alga Chlamydomonas reinhardtii have been investigated using site-directed mutagenesis. The results indicate that a single C-terminal disulfide is responsible for this regulation. The redox midpoint potential of this disulfide is less negative than that of the higher plant enzyme. The regulation is of an all-or-nothing type, lacking the fine-tuning provided by the second N-terminal disulfide found only in NADP-MDH from higher plants. The decreased stability of specific cysteine/alanine mutants is consistent with the presence of a structural disulfide formed by two cysteine residues that are not involved in regulation of activity. Measurements of the ability of C. reinhardtii thioredoxin f (TRX f) to activate wild-type and site-directed mutants of sorghum (Sorghum vulgare) NADP-MDH suggest that the algal TRX f has a redox midpoint potential that is less negative than most those of higher plant TRXs f. These results are discussed from an evolutionary point of view. [ABSTRACT FROM AUTHOR]
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NADP-Malate Dehydrogenase from Unicellular Green Alga Chlamydomonas reinhardtii. A First Step toward Redox Regulation?
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Autor/in / Beteiligte Person: | Lemaire, Stéphane D. ; Quesada, Alberto ; Merchan, Faustino ; Corral, Juan Manuel ; Igeno, Maria Isabel ; Keryer, Eliane ; Issakidis-Bourguet, Emmanuelle ; Hirasawa, Masakazu ; Knaff, David B. ; Miginiac-Maslow, Myroslawa |
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Zeitschrift: | Plant Physiology, Jg. 137 (2005-02-01), Heft 2, S. 514-521 |
Veröffentlichung: | 2005 |
Medientyp: | academicJournal |
ISSN: | 0032-0889 (print) |
DOI: | 10.1104/pp.104.052670 |
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