Pyruvate:Ferredoxin Oxidoreductase Is Coupled to Light-independent Hydrogen Production in Chlamydomonas reinhardtii

Noth, Jens; Krawietz, Danuta; Hemschemeier, Anja; Happe, Thomas

doi:10.1074/jbc.m112.429985

Cited by 80 publications

(61 citation statements)

References 93 publications

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“…It is also important to note that pyruvate decarboxylation is a source of acetyl-CoA that can be use as a substrate by the FDX-dependent enzyme, pyruvate-ferredoxin oxidoreductase, which in turn transfers electrons to the hydrogenase for hydrogen production under dark anaerobiosis. It has been shown that FDX1 is the best mediator (compared with the other five FDXs) for providing electrons to the pyruvate-ferredoxin oxidoreductase enzyme and drives the best hydrogen production rate (63,64).…”

Section: Discussionmentioning

confidence: 99%

Identification of Global Ferredoxin Interaction Networks in Chlamydomonas reinhardtii

Peden

Boehm

Mulder

et al. 2013

Journal of Biological Chemistry

100

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Background: Chlamydomonas contains six chloroplast ferredoxins (FDXs) whose function is still unclear. Results: A global FDX interactome was obtained where FDX1 has a predominant role and is the most relevant electron donor to FNR1 and HYDA1. Conclusion: FDXs have distinct but also overlapping function. Significance: We discovered new FDX interaction partners and specific roles for each FDX isoform.

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Section: Discussionmentioning

confidence: 99%

Identification of Global Ferredoxin Interaction Networks in Chlamydomonas reinhardtii

Peden

Boehm

Mulder

et al. 2013

Journal of Biological Chemistry

100

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“…Using a yeast two hybrid approach, a global FDX interaction network was established for Chlamydomonas, suggesting putative roles for FDX1 (originally designated Fd) in redox metabolism, carbohydrate modification, and fatty acid biosynthesis (5); this FDX was already known to function in both linear and cyclic photosynthetic electron flow (4,6). FDX1 also accepts electrons from FDX-NADP oxidoreductase (FNR) (7) and donates electrons to HYDA hydrogenases (5,8,9). Other FDXs may be involved in state transitions, nitrogen metabolism, cellular responses to reactive oxygen species (ROS), and dark anoxia (4,5,(10)(11)(12)(13).…”

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confidence: 99%

Critical role of Chlamydomonas reinhardtii ferredoxin-5 in maintaining membrane structure and dark metabolism

Yang

Wittkopp

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Photosynthetic microorganisms typically have multiple isoforms of the electron transfer protein ferredoxin, although we know little about their exact functions. Surprisingly, a Chlamydomonas reinhardtii mutant null for the ferredoxin-5 gene (FDX5) completely ceased growth in the dark, with both photosynthetic and respiratory functions severely compromised; growth in the light was unaffected. Thylakoid membranes in dark-maintained fdx5 mutant cells became severely disorganized concomitant with a marked decrease in the ratio of monogalactosyldiacylglycerol to digalactosyldiacylglycerol, major lipids in photosynthetic membranes, and the accumulation of triacylglycerol. Furthermore, FDX5 was shown to physically interact with the fatty acid desaturases CrΔ4FAD and CrFAD6, likely donating electrons for the desaturation of fatty acids that stabilize monogalactosyldiacylglycerol. Our results suggest that in photosynthetic organisms, specific redox reactions sustain dark metabolism, with little impact on daytime growth, likely reflecting the tailoring of electron carriers to unique intracellular metabolic circuits under these two very distinct redox conditions. ferredoxin | dark growth | thylakoid lipids | triacylglycerol | redox regulation F erredoxins (FDXs) are soluble, iron-sulfur proteins that mediate electron transfer in a variety of essential metabolic reactions (1-3) (SI Appendix, Fig. S1). The Chlamydomonas genome encodes 13 FDXs (SI Appendix, Table S1) with localization and redox properties that suggest involvement in specific redox reactions (4). Using a yeast two hybrid approach, a global FDX interaction network was established for Chlamydomonas, suggesting putative roles for FDX1 (originally designated Fd) in redox metabolism, carbohydrate modification, and fatty acid biosynthesis (5); this FDX was already known to function in both linear and cyclic photosynthetic electron flow (4, 6). FDX1 also accepts electrons from FDX-NADP oxidoreductase (FNR) (7) and donates electrons to HYDA hydrogenases (5,8,9). Other FDXs may be involved in state transitions, nitrogen metabolism, cellular responses to reactive oxygen species (ROS), and dark anoxia (4, 5, 10-13).The major lipids in thylakoid membranes are monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), phosphatidylglycerol (PG), and sulfoquinovosyldiacylglycerol (SQDG) (14-17), with MGDG being the most abundant, followed by DGDG (14, 17). In Arabidopsis, three enzyme systems are involved in MGDG and DGDG synthesis (18). In contrast, there is only a single copy each of an MGDG and DGDG synthase gene in Chlamydomonas (19). Chlamydomonas uses the prokaryotic pathway for thylakoid lipid synthesis (20) in which the MGDG species synthesized in chloroplasts contain predominantly C18:3 Δ9,12,15 -sn-1 with the unusual hexadeca-4, 7, 10, 13-tetraenoic acid C16:4 Δ4,7,10,13 at the sn-2 position (20). Desaturation of the sn-2 acyl group of Chlamydomonas MGDG requires the CrΔ4FAD desaturase, which is not present in Arabidopsis (21), and MGDG accumulation in...

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“…The presence of these bacterial-type enzymes raises questions about their evolutionary origin and their integration in a mitochondriate eukaryote that we and others have tackled since their discovery. PFL and PFO were both shown to be functional in C. reinhardtii (16,18,19) and can, under anaerobic conditions, catalyze the production of acetyl-CoA from pyruvate. PFL accumulates under aerobic conditions and is dually targeted to chloroplast and mitochondria (12).…”

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confidence: 99%

“…The genome sequences of Chlamydomonas reinhardtii (10) and Chlorella variabilis NC64 (11) have greatly helped to get a good grasp of the anaerobic pathways in the two algae (12)(13)(14). Since then, in C. reinhardtii, these pathways have been actively investigated through molecular and biochemical studies of the fermentative enzymes (15)(16)(17)(18)(19), as well as physiological studies of mutant strains (20 -25). As we understand it, the "core" anaerobic network in the chlorophyte combines enzymes commonly found in eukaryotes, i.e.…”

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confidence: 99%

“…PFL accumulates under aerobic conditions and is dually targeted to chloroplast and mitochondria (12). PFO is expressed under anaerobic conditions and localizes to the chloroplast where it is coupled to H 2 production by iron-only hydrogenases via FDX1 (PetF) (18,19). ADHE is a mono-iron enzyme, which was found to be the major ethanol-producing enzyme in conditions of dark anoxia (22).…”

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confidence: 99%

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Concerted Up-regulation of Aldehyde/Alcohol Dehydrogenase (ADHE) and Starch in Chlamydomonas reinhardtii Increases Survival under Dark Anoxia

Lis

Popek

Couté

et al. 2017

Journal of Biological Chemistry

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Edited by Joseph JezAldehyde/alcohol dehydrogenases (ADHEs) are bifunctional enzymes that commonly produce ethanol from acetyl-CoA with acetaldehyde as intermediate and play a key role in anaerobic redox balance in many fermenting bacteria. ADHEs are also present in photosynthetic unicellular eukaryotes, where their physiological role and regulation are, however, largely unknown. Herein we provide the first molecular and enzymatic characterization of the ADHE from the photosynthetic microalga Chlamydomonas reinhardtii. Purified recombinant ADHE catalyzed the reversible NADH-mediated interconversions of acetyl-CoA, acetaldehyde, and ethanol but seemed to be poised toward the production of ethanol from acetaldehyde. Phylogenetic analysis of the algal fermentative enzyme supports a vertical inheritance from a cyanobacterial-related ancestor. ADHE was located in the chloroplast, where it associated in dimers and higher order oligomers. Electron microscopy analysis of ADHE-enriched stromal fractions revealed fine spiral structures, similar to bacterial ADHE spirosomes. Protein blots showed that ADHE is regulated under oxic conditions. Up-regulation is observed in cells exposed to diverse physiological stresses, including zinc deficiency, nitrogen starvation, and inhibition of carbon concentration/fixation capacity. Analyses of the overall proteome and fermentation profiles revealed that cells with increased ADHE abundance exhibit better survival under dark anoxia. This likely relates to the fact that greater ADHE abundance appeared to coincide with enhanced starch accumulation, which might reflect ADHE-mediated anticipation of anaerobic survival.Oxygenic photosynthetic microorganisms are typically associated with illuminated oxic environments, and so, little attention is paid to energy generation in conditions of dark anoxia.

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Pyruvate:Ferredoxin Oxidoreductase Is Coupled to Light-independent Hydrogen Production in Chlamydomonas reinhardtii

Cited by 80 publications

References 93 publications

Identification of Global Ferredoxin Interaction Networks in Chlamydomonas reinhardtii

Identification of Global Ferredoxin Interaction Networks in Chlamydomonas reinhardtii

Critical role of Chlamydomonas reinhardtii ferredoxin-5 in maintaining membrane structure and dark metabolism

Concerted Up-regulation of Aldehyde/Alcohol Dehydrogenase (ADHE) and Starch in Chlamydomonas reinhardtii Increases Survival under Dark Anoxia

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