A second isoform of the ferredoxin:NADP oxidoreductase generated by an in-frame initiation of translation

Thomas, Jean‐Claude; Ughy, Bettina; Lagoutte, Bernard; Ajlani, Ghada

doi:10.1073/pnas.0607718103

Cited by 83 publications

(110 citation statements)

References 35 publications

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“…In Synechocystis 6803, a second isoform of the ferredoxin:NADP oxidoreductase is generated by an in-frame initiation of translation from the petH gene (35). Although such cases generally have been sparse in bacteria (36), we speculate that some of the iTSS reported here could produce shorter isoforms of Synechocystis 6803 proteins.…”

Section: Discussionmentioning

confidence: 81%

An experimentally anchored map of transcriptional start sites in the model cyanobacterium Synechocystis sp. PCC6803

Mitschke

Georg

Scholz

et al. 2011

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

349

459

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There has been an increasing interest in cyanobacteria because these photosynthetic organisms convert solar energy into biomass and because of their potential for the production of biofuels. However, the exploitation of cyanobacteria for bioengineering requires knowledge of their transcriptional organization. Using differential RNA sequencing, we have established a genome-wide map of 3,527 transcriptional start sites (TSS) of the model organism Synechocystis sp. PCC6803. One-third of all TSS were located upstream of an annotated gene; another third were on the reverse complementary strand of 866 genes, suggesting massive antisense transcription. Orphan TSS located in intergenic regions led us to predict 314 noncoding RNAs (ncRNAs). Complementary microarray-based RNA profiling verified a high number of noncoding transcripts and identified strong ncRNA regulations. Thus, ∼64% of all TSS give rise to antisense or ncRNAs in a genome that is to 87% protein coding. Our data enhance the information on promoters by a factor of 40, suggest the existence of additional small peptide-encoding mRNAs, and provide corrected 5′ annotations for many genes of this cyanobacterium. The global TSS map will facilitate the use of Synechocystis sp. PCC6803 as a model organism for further research on photosynthesis and energy research.gene expression regulation | promoter prediction | RNA polymerase

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Section: Discussionmentioning

confidence: 81%

An experimentally anchored map of transcriptional start sites in the model cyanobacterium Synechocystis sp. PCC6803

Mitschke

Georg

Scholz

et al. 2011

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

349

459

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“…In the PAL mutant in which PBs are completely absent (Ajlani and Vernotte, 1998), no flv4-2 operon-encoded proteins were detected. In the CK mutant (DcpcC; constructed by Ughy and Ajlani and described in Thomas et al, 2006) containing PBs deprived of phycocyanin rods and composed of only the allophycocyanin core, the amounts of Flv4, Sll0218, and Flv2 proteins were reduced by approximately 75% compared with those in the wild type. In the DApcDF mutant (Jallet et al, 2012) that lacks the allophycocyanin D and allophycocyanin F terminal emitters (emitting at 680 nm), a severe reduction in energy transfer from PBs to the PSII reaction centers has been demonstrated (Ashby and Mullineaux, 1999;Jallet et al, 2012).…”

Section: Relation Of Flv4-2 Operon With Pbsmentioning

confidence: 99%

Flavodiiron Protein Flv2/Flv4-Related Photoprotective Mechanism Dissipates Excitation Pressure of PSII in Cooperation with Phycobilisomes in Cyanobacteria

et al. 2013

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(A.R., I.V.) Oxygenic photosynthesis evolved with cyanobacteria, the ancestors of plant chloroplasts. The highly oxidizing chemistry of water splitting required concomitant evolution of efficient photoprotection mechanisms to safeguard the photosynthetic machinery. The role of flavodiiron proteins (FDPs), originally called A-type flavoproteins or Flvs, in this context has only recently been appreciated. Cyanobacterial FDPs constitute a specific protein group that evolved to protect oxygenic photosynthesis. There are four FDPs in Synechocystis sp. PCC 6803 (Flv1 to Flv4). Two of them, Flv2 and Flv4, are encoded by an operon together with a Sll0218 protein.Their expression, tightly regulated by CO 2 levels, is also influenced by changes in light intensity. Here we describe the overexpression of the flv4-2 operon in Synechocystis sp. PCC 6803 and demonstrate that it results in improved photochemistry of PSII. The flv4-2/OE mutant is more resistant to photoinhibition of PSII and exhibits a more oxidized state of the plastoquinone pool and reduced production of singlet oxygen compared with control strains. Results of biophysical measurements indicate that the flv4-2 operon functions in an alternative electron transfer pathway from PSII, and thus alleviates PSII excitation pressure by channeling up to 30% of PSII-originated electrons. Furthermore, intact phycobilisomes are required for stable expression of the flv4-2 operon genes and for the Flv2/Flv4 heterodimer-mediated electron transfer mechanism. The latter operates in photoprotection in a complementary way with the orange carotenoid protein-related nonphotochemical quenching. Expression of the flv4-2 operon and exchange of the D1 forms in PSII centers upon light stress, on the contrary, are mutually exclusive photoprotection strategies among cyanobacteria.Photosynthetic light reactions are evolutionarily highly conserved among oxygenic photosynthetic organisms from cyanobacteria to higher plants. Because of dangerous chemistry of the water splitting reactions, oxygenic photosynthesis produces reactive oxygen species (ROS) and other radicals that potentially could destroy the photosynthetic machinery. To avoid permanent damage, all oxygenic photosynthetic organisms are equipped with an array of various photoprotective and regulatory mechanisms. Accumulating evidence on these regulatory mechanisms has revealed vast evolutionary differences between organisms performing oxygenic photosynthesis.Photosynthetic organisms have a capacity to adjust to different light intensities and to changes in the availability of electron sinks, which depends largely on metabolic cues. When light or metabolic conditions change, photosystems can dissipate excess energy as heat in nonphotochemical energy dissipation processes in the light-harvesting antenna systems (for review, see Horton et al., 1996;Müller et al., 2001). Cyanobacteria have phycobilisomes (PBs) as light-harvesting antenna, which also participate in state transitions (for review, see van Thor et al., 1998;Mullineaux ...

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“…5A). This form of FNR oxidizes NADPH and accumulates in heterotrophic conditions, possibly enhancing CET by transferring electrons via ferredoxin to NDH-1 (Thomas et al, 2006;Korn, 2010). The elevated CET in the mutant was accompanied by an increase of the Cyt b 6 f complex (PetA,B,C,D; Table III).…”

Section: The Deletion Of Ndbc Alters the Expression Of Multiple Transmentioning

confidence: 99%

Role of Type 2 NAD(P)H Dehydrogenase NdbC in Redox Regulation of Carbon Allocation in Synechocystis

et al. 2017

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H dehydrogenases comprise type 1 (NDH-1) and type 2 (NDH-2s) enzymes. Even though the NDH-1 complex is a wellcharacterized protein complex in the thylakoid membrane of Synechocystis sp. PCC 6803 (hereafter Synechocystis), the exact roles of different NDH-2s remain poorly understood. To elucidate this question, we studied the function of NdbC, one of the three NDH-2s in Synechocystis, by constructing a deletion mutant (DndbC) for a corresponding protein and submitting the mutant to physiological and biochemical characterization as well as to comprehensive proteomics analysis. We demonstrate that the deletion of NdbC, localized to the plasma membrane, affects several metabolic pathways in Synechocystis in autotrophic growth conditions without prominent effects on photosynthesis. Foremost, the deletion of NdbC leads, directly or indirectly, to compromised sugar catabolism, to glycogen accumulation, and to distorted cell division. Deficiencies in several sugar catabolic routes were supported by severe retardation of growth of the DndbC mutant under light-activated heterotrophic growth conditions but not under mixotrophy. Thus, NdbC has a significant function in regulating carbon allocation between storage and the biosynthesis pathways. In addition, the deletion of NdbC increases the amount of cyclic electron transfer, possibly via the NDH-1 2 complex, and decreases the expression of several transporters in ambient CO 2 growth conditions.

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A second isoform of the ferredoxin:NADP oxidoreductase generated by an in-frame initiation of translation

Cited by 83 publications

References 35 publications

An experimentally anchored map of transcriptional start sites in the model cyanobacterium Synechocystis sp. PCC6803

An experimentally anchored map of transcriptional start sites in the model cyanobacterium Synechocystis sp. PCC6803

Flavodiiron Protein Flv2/Flv4-Related Photoprotective Mechanism Dissipates Excitation Pressure of PSII in Cooperation with Phycobilisomes in Cyanobacteria

Role of Type 2 NAD(P)H Dehydrogenase NdbC in Redox Regulation of Carbon Allocation in Synechocystis

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