Ferredoxin and Ferredoxin-Dependent Enzymes

Knaff, David B.

doi:10.1007/0-306-48127-8_17

Cited by 85 publications

(53 citation statements)

References 236 publications

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“…The [4Fe-4S] clusters in turn reduce the [2Fe-2S] cluster of soluble ferredoxin. After being reduced by PsaC, ferredoxins can function as general soluble electron donors in the stroma, which initialize a number of important biological processes (Knaff 1996). A well-known function is the transfer of electrons to NADP + through the flavoenzyme ferredoxin:NADP + reductase.…”

Section: Reduced Ferredoxin Is Produced In the Light Reaction Of Photmentioning

confidence: 99%

“…This system is composed of three soluble chloroplast proteins, ferredoxin, ferredoxin:thioredoxin reductase (FTR) and thioredoxins (Schürmann 2003). In the light, ferredoxin is reduced by the photosynthetic electron transport and transmits electrons to various enzymes like ferredoxin:NADP + reductase, ferredoxin:nitrite reductase, sulfite reductase, glutamate synthase and FTR (Knaff 1996). The FTR, the central enzyme of the ferredoxin/thioredoxin regulatory system, transforms the electron signal into a disulfide/dithiol signal ( Figure 1).…”

Section: Introductionmentioning

confidence: 99%

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Structural Basis of Redox Signaling in Photosynthesis: Structure and Function of Ferredoxin:thioredoxin Reductase and Target Enzymes

Dai

Johansson

Miginiac‐Maslow

et al. 2004

Photosynthesis Research

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The role of the ferredoxin:thioredoxin system in the reversible light activation of chloroplast enzymes by thioldisulfide interchange with thioredoxins is now well established. Recent fruitful collaboration between biochemists and structural biologists, reflected by the shared authorship of the paper, allowed to solve the structures of all of the components of the system, including several target enzymes, thus providing a structural basis for the elucidation of the activation mechanism at a molecular level. In the present Review, these structural data are analyzed in conjunction with the information that was obtained previously through biochemical and site-directed mutagenesis approaches. The unique 4Fe-4S cluster enzyme ferredoxin:thioredoxin reductase (FTR) uses photosynthetically reduced ferredoxin as an electron donor to reduce the disulfide bridge of different thioredoxin isoforms. Thioredoxins in turn reduce regulatory disulfides of various target enzymes. This process triggers conformational changes on these enzymes, allowing them to reach optimal activity. No common activation mechanism can be put forward for these enzymes, as every thioredoxin-regulated protein undergoes specific structural modifications. It is thus important to solve the structures of the individual target enzymes in order to fully understand the molecular mechanism of the redox regulation of each of them.Abbreviations: FBPase -fructose-

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Section: Reduced Ferredoxin Is Produced In the Light Reaction Of Photmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structural Basis of Redox Signaling in Photosynthesis: Structure and Function of Ferredoxin:thioredoxin Reductase and Target Enzymes

Dai

Johansson

Miginiac‐Maslow

et al. 2004

Photosynthesis Research

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“…Ferredoxins (Fds) are ubiquitous iron-sulfur proteins involved in many different electron transfer pathways in plants, animals, and microorganisms (Knaff, 2005). As the major low-potential mobile electron carrier protein of chloroplasts, Fd plays a central role in the physiology of the plant cell, distributing the reducing equivalents generated in the photosynthetic electron transport chain (PETC) to various electron-consuming reactions of the chloroplast.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, Fd is a key player in different routes of cyclic electron flow that operate under physiological and stress conditions to eliminate the excess of reducing power and prevent uncontrolled overreduced states in the PETC and the stroma (Kramer et al, 2004;Munekage et al, 2004). The Fd redox state also functions as a signal in the intracellular signaling pathway between chloroplast and nucleus (Knaff, 2005). The various Fd acceptors are organized in a hierarchical manner, attaining their maximal activities at different electronic pressures (Backhausen et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Functional Replacement of Ferredoxin by a Cyanobacterial Flavodoxin in Tobacco Confers Broad-Range Stress Tolerance

et al. 2006

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Chloroplast ferredoxin (Fd) plays a pivotal role in plant cell metabolism by delivering reducing equivalents to various essential oxidoreductive pathways. Fd levels decrease under adverse environmental conditions in many microorganisms, including cyanobacteria, which share a common ancestor with chloroplasts. Conversely, stress situations induce the synthesis of flavodoxin (Fld), an electron carrier flavoprotein not found in plants, which can efficiently replace Fd in most electron transfer processes. We report here that chloroplast Fd also declined in plants exposed to oxidants or stress conditions. A purified cyanobacterial Fld was able to mediate plant Fd-dependent reactions in vitro, including NADP 1 and thioredoxin reduction. Tobacco (Nicotiana tabacum) plants expressing Fld in chloroplasts displayed increased tolerance to multiple sources of stress, including redox-cycling herbicides, extreme temperatures, high irradiation, water deficit, and UV radiation. Oxidant buildup and oxidative inactivation of thioredoxin-dependent plastidic enzymes were decreased in stressed plants expressing plastid-targeted Fld, suggesting that development of the tolerant phenotype relied on productive interaction of this flavoprotein with Fd-dependent oxidoreductive pathways of the host, most remarkably, thioredoxin reduction. The use of Fld provides new tools to investigate the requirements of photosynthesis in planta and to increase plant stress tolerance based on the introduction of a cyanobacterial product that is free from endogenous regulation in higher plants.

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“…They shuttle low potential electrons between different donors and acceptors in redox-based metabolisms of a number of bacteria and eukaryotic algae (1,2). Their functions largely match those of ferredoxins (Fds), ubiquitous redox carriers that utilize iron-sulphur centres of different stoichiometries as prosthetic groups (3). Fld and Fd do not share significant sequence or structural similarities and still they can interact productively with the same redox partners with equivalent efficiency.…”

Section: Introductionmentioning

confidence: 99%

Stress‐inducible flavodoxin from photosynthetic microorganisms. The mystery of flavodoxin loss from the plant genome

2007

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SummaryFlavodoxins (Flds) are mobile electron carriers containing flavin mononucleotide as the prosthetic group. They are isofunctional with the ubiquitous electron shuttle ferredoxin (Fd), mediating essentially the same redox processes among a promiscuous lot of donors and acceptors. While Fds are distributed throughout all kingdoms from prokaryotes to animals, Flds are only found in some bacteria and oceanic algae, in which they are induced to replace Fd functions under conditions of iron starvation and environmental stress that cause Fd decline. They thus play a key adaptive role in photosynthetic microorganisms, allowing survival and reproduction under adverse situations. The Fld gene disappeared from the plant genome somewhere between the green algal ancestor and the first terrestrial plants, and the advantages of this adaptive resource were irreversibly lost. However, reintroduction of a cyanobacterial Fld gene in the chloroplasts of transgenic tobacco resulted in remarkably enhanced tolerance to iron starvation and abiotic stress, indicating that the compensatory functions of Fld were still valuable in higher plants. A hypothesis is formulated to explain why Fld, in spite of its proven advantage, was lost from the plant genetic pool. The contention is based on two tenets: (i) iron availability was the major imperative for Fld conservation and adaptive value, and (ii) photosynthetic eukaryotes followed a succession of ecological adaptations, from the open oceans to coastal regions, and from there to the firm land, facing very different scenarios with respect to iron abundance and accessibility. IUBMB Life, 59: 355-360, 2007

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Ferredoxin and Ferredoxin-Dependent Enzymes

Cited by 85 publications

References 236 publications

Structural Basis of Redox Signaling in Photosynthesis: Structure and Function of Ferredoxin:thioredoxin Reductase and Target Enzymes

Structural Basis of Redox Signaling in Photosynthesis: Structure and Function of Ferredoxin:thioredoxin Reductase and Target Enzymes

Functional Replacement of Ferredoxin by a Cyanobacterial Flavodoxin in Tobacco Confers Broad-Range Stress Tolerance

Stress‐inducible flavodoxin from photosynthetic microorganisms. The mystery of flavodoxin loss from the plant genome

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