Module fusion in an A-type flavoprotein from the cyanobacterium Synechocystis condenses a multiple-component pathway in a single polypeptide chain

Vicente, João B.; Gomes, Cláudio M.; Wasserfallen, Alain; Teixeira, Miguel

doi:10.1016/s0006-291x(02)00434-5

Cited by 101 publications

(96 citation statements)

References 23 publications

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“…S6). These data suggest that FLV2/4 mediates an oxygen-dependent AEF on the acceptor side of PSI (Hayashi et al, 2014;Shimakawa et al, 2015), as does FLV1/3 (Helman et al, 2003), since both FLV sets have similar primary structures (Fujisawa et al, 2014) and enzymatic characteristics of recombinant proteins (Vicente et al, 2002;Shimakawa et al, 2015). However, we cannot exclude the possibility that the relief of excitation pressure at PSII by FLV2/4 (Bersanini et al, 2014) provides an enhancement of Y(I) during CO 2 -limited photosynthesis in S. 6803.…”

Section: Discussionmentioning

confidence: 87%

“…PCC 6803 (S. 6803; Helman et al, 2003). FLV1 and FLV3 (FLV1/3) function as a heterodimer and catalyze the reduction of oxygen to water on the acceptor side of PSI using NAD(P)H as electron donors (Vicente et al, 2002;Helman et al, 2003;Allahverdiyeva et al, 2013). Unlike FLV1/3, FLV2/4 is induced only under low CO 2 (Zhang et al, 2009) and mediates an oxygen-dependent alternative electron flow (AEF; Shimakawa et al, 2015).…”

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confidence: 99%

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Oxidation of P700 in Photosystem I Is Essential for the Growth of Cyanobacteria

2016

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The photoinhibition of photosystem I (PSI) is lethal to oxygenic phototrophs. Nevertheless, it is unclear how photodamage occurs or how oxygenic phototrophs prevent it. Here, we provide evidence that keeping P700 (the reaction center chlorophyll in PSI) oxidized protects PSI. Previous studies have suggested that PSI photoinhibition does not occur in the two model cyanobacteria, Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942, when photosynthetic CO 2 fixation was suppressed under low CO 2 partial pressure even in mutants deficient in flavodiiron protein (FLV), which mediates alternative electron flow. The lack of FLV in Synechococcus sp. PCC 7002 (S. 7002), however, is linked directly to reduced growth and PSI photodamage under CO 2 -limiting conditions. Unlike Synechocystis sp. PCC 6803 and S. elongatus PCC 7942, S. 7002 reduced P700 during CO 2 -limited illumination in the absence of FLV, resulting in decreases in both PSI and photosynthetic activities. Even at normal air CO 2 concentration, the growth of S. 7002 mutant was retarded relative to that of the wild type. Therefore, P700 oxidation is essential for protecting PSI against photoinhibition. Here, we present various strategies to alleviate PSI photoinhibition in cyanobacteria.Low CO 2 fixation efficiency in the Calvin-Benson cycle prevents the utilization of NADPH and ATP in photosynthesis and causes these molecules to accumulate, resulting in oxidative photosynthetic cell damage. High light, low temperature, and CO 2 limitation increase NADPH and ATP levels beyond the Calvin-Benson cycle requirements. Electrons and H +

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Section: Discussionmentioning

confidence: 87%

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confidence: 99%

Oxidation of P700 in Photosystem I Is Essential for the Growth of Cyanobacteria

2016

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“…The reaction, which in other organisms requires several steps, is condensed to a single protein (Vicente et al, 2002). Due to unavailability of structures with all three domains, the flavin reductase domains of Flv2 and Flv4 were modeled as separate monomers ( Figures 8C and 8D) based on Archaeoglobus fulgidus FeR (PDB ID: 1I0S) (Chiu et al, 2001).…”

Section: Psii Function In Flv4-flv2 Operon Mutantsmentioning

confidence: 99%

“…jp/cyanobase/). Recombinant Synechocystis Flv3 homodimer has been shown to have NAD(P)H:oxygen oxidoreductase activity (Vicente et al, 2002). It was soon confirmed by in vivo studies that Synechocystis Flv1 and Flv3 function in the Mehler-like reaction, which acquires electrons after photosystem I (PSI) to reduce molecular oxygen to water like the real Mehler reaction but differs from that by no concomitant formation of reactive oxygen species (Helman et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Operon flv4-flv2 Provides Cyanobacterial Photosystem II with Flexibility of Electron Transfer

et al. 2012

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Synechocystis sp PCC 6803 has four genes encoding flavodiiron proteins (FDPs; Flv1 to Flv4). Here, we investigated the flv4-flv2 operon encoding the Flv4, Sll0218, and Flv2 proteins, which are strongly expressed under low inorganic carbon conditions (i.e., air level of CO 2 ) but become repressed at elevated CO 2 conditions. Different from FDP homodimers in anaerobic microbes, Synechocystis Flv2 and Flv4 form a heterodimer. It is located in cytoplasm but also has a high affinity to membrane in the presence of cations. Sll0218, on the contrary, resides in the thylakoid membrane in association with a high molecular mass protein complex. Sll0218 operates partially independently of Flv2/Flv4. It stabilizes the photosystem II (PSII) dimers, and according to biophysical measurements opens up a novel electron transfer pathway to the Flv2/Flv4 heterodimer from PSII. Constructed homology models suggest efficient electron transfer in heterodimeric Flv2/Flv4. It is suggested that Flv2/Flv4 binds to thylakoids in light, mediates electron transfer from PSII, and concomitantly regulates the association of phycobilisomes with PSII. The function of the flv4-flv2 operon provides many b-cyanobacteria with a so far unknown photoprotection mechanism that evolved in parallel with oxygen-evolving PSII.

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“…The physiological function of the different O 2 photoreduction pathways has been controversial, since they have been alternatively viewed as futile pathways resulting in a waste of energy, as protective mechanisms avoiding photooxidative damage, or as a mean to (re)-equilibrate the balance between reducing and phosphorylating powers through pseudocyclic photophosphorylations (Badger, 1985;Allen, 2003). In cyanobacteria, flavodiiron proteins catalyze NADPH-dependent reduction of O 2 at the PSI acceptor side (Vicente et al, 2002;Helman et al, 2003;Allahverdiyeva et al, 2013). The Synechocystis sp.…”

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confidence: 99%

Flavodiiron Proteins Promote Fast and Transient O₂ Photoreduction in Chlamydomonas

et al. 2017

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During oxygenic photosynthesis, the reducing power generated by light energy conversion is mainly used to reduce carbon dioxide. In bacteria and archae, flavodiiron (Flv) proteins catalyze O 2 or NO reduction, thus protecting cells against oxidative or nitrosative stress. These proteins are found in cyanobacteria, mosses, and microalgae, but have been lost in angiosperms. Here, we used chlorophyll fluorescence and oxygen exchange measurement using [18 O]-labeled O 2 and a membrane inlet mass spectrometer to characterize Chlamydomonas reinhardtii flvB insertion mutants devoid of both FlvB and FlvA proteins. We show that Flv proteins are involved in a photo-dependent electron flow to oxygen, which drives most of the photosynthetic electron flow during the induction of photosynthesis. As a consequence, the chlorophyll fluorescence patterns are strongly affected in flvB mutants during a light transient, showing a lower PSII operating yield and a slower nonphotochemical quenching induction. Photoautotrophic growth of flvB mutants was indistinguishable from the wild type under constant light, but severely impaired under fluctuating light due to PSI photo damage. Remarkably, net photosynthesis of flv mutants was higher than in the wild type during the initial hour of a fluctuating light regime, but this advantage vanished under longterm exposure, and turned into PSI photo damage, thus explaining the marked growth retardation observed in these conditions. We conclude that the C. reinhardtii Flv participates in a Mehler-like reduction of O 2 , which drives a large part of the photosynthetic electron flow during a light transient and is thus critical for growth under fluctuating light regimes.

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Module fusion in an A-type flavoprotein from the cyanobacterium Synechocystis condenses a multiple-component pathway in a single polypeptide chain

Cited by 101 publications

References 23 publications

Oxidation of P700 in Photosystem I Is Essential for the Growth of Cyanobacteria

Oxidation of P700 in Photosystem I Is Essential for the Growth of Cyanobacteria

Operon flv4-flv2 Provides Cyanobacterial Photosystem II with Flexibility of Electron Transfer

Flavodiiron Proteins Promote Fast and Transient O₂ Photoreduction in Chlamydomonas

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Module fusion in an A-type flavoprotein from the cyanobacterium Synechocystis condenses a multiple-component pathway in a single polypeptide chain

Cited by 101 publications

References 23 publications

Oxidation of P700 in Photosystem I Is Essential for the Growth of Cyanobacteria

Oxidation of P700 in Photosystem I Is Essential for the Growth of Cyanobacteria

Operon flv4-flv2 Provides Cyanobacterial Photosystem II with Flexibility of Electron Transfer

Flavodiiron Proteins Promote Fast and Transient O2 Photoreduction in Chlamydomonas

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Flavodiiron Proteins Promote Fast and Transient O₂ Photoreduction in Chlamydomonas