Structural adaptations of photosynthetic complex I enable ferredoxin-dependent electron transfer

Schuller, Jan M.; Birrell, James A.; Tanaka, Hideaki; Konuma, Tsuyoshi; Wulfhorst, Hannes; Cox, Nicholas; Schuller, Sandra K.; Thiemann, Jacqueline; Lubitz, Wolfgang; Sétif, Pièrre; Ikegami, Takahisa; Engel, Benjamin D.; Kurisu, Genji; Nowaczyk, Marc M.

doi:10.1126/science.aau3613

Cited by 176 publications

(158 citation statements)

References 87 publications

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“…Instead, the electrons directly enter a chain of three iron-sulphur (FeS) centres in the ferredoxin (Fd)binding domain (Fig. 1d), similar to the recently characterised NDH-1L type photosynthetic complex I and membrane-bound hydrogenases [15][16][17][18] . The PQ-binding site is located ca.…”

Section: Resultsmentioning

confidence: 61%

“…The modular membrane domain extends up to 200 Å away from the PQ reduction site, and it comprises the antiporter-like subunits NdhA, NdhB, NdhD3, and NdhF3, as well as the smaller transmembrane (TM) subunits NdhC/E/G/L. These subunits contain a chain of buried charged residues that establish central elements of the proton-pumping machinery [11][12][13][14][15][16][17]19,20 , with the isoform-specific NdhD3 and NdhF3 subunits at the terminal end of the enzyme (Fig. 1d, see below).…”

Section: Resultsmentioning

confidence: 99%

“…Cells of the fully segregated mutant were grown in liquid BG-11 medium and expression of the NDH-1MS complex was induced by low CO 2 growth conditions. Preparation of the thylakoid membranes and isolation of the tagged complex were performed as described earlier 15,33 with minor modifications. See SI Materials and Methods for details.…”

Section: Methodsmentioning

confidence: 99%

“…Model building and validation. The models for the conserved subunits were taken from the previously published NDH-1L complex (PDB ID: 6HUM) 15 . For the NdhD3 and NdhF3 paralog subunits homology models were generated with the Phyre2 server and fitted as rigid bodies with UCSF Chimera 39 .…”

Section: Methodsmentioning

confidence: 99%

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Redox-coupled proton pumping drives carbon concentration in the photosynthetic complex I

et al. 2020

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Photosynthetic organisms capture light energy to drive their energy metabolism, and employ the chemical reducing power to convert carbon dioxide (CO 2 ) into organic molecules. Photorespiration, however, significantly reduces the photosynthetic yields. To survive under low CO 2 concentrations, cyanobacteria evolved unique carbon-concentration mechanisms that enhance the efficiency of photosynthetic CO 2 fixation, for which the molecular principles have remained unknown. We show here how modular adaptations enabled the cyanobacterial photosynthetic complex I to concentrate CO 2 using a redox-driven proton-pumping machinery. Our cryo-electron microscopy structure at 3.2 Å resolution shows a catalytic carbonic anhydrase module that harbours a Zn 2+ active site, with connectivity to protonpumping subunits that are activated by electron transfer from photosystem I. Our findings illustrate molecular principles in the photosynthetic complex I machinery that enabled cyanobacteria to survive in drastically changing CO 2 conditions.

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Section: Resultsmentioning

confidence: 61%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Redox-coupled proton pumping drives carbon concentration in the photosynthetic complex I

et al. 2020

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“…Cyclic electron flow around PSI in cyanobacteria is currently thought to occur via two main routes: the NDH (NADH dehydrogenase-like) pathway, involving a PSI/NDH-1 supercomplex (Gao et al, 2016;Schuller et al, 2019), and the poorly characterized antimycin-sensitive Pgr5 pathway (Yeremenko et al, 2005). In plant chloroplasts, PGR5 is thought to function as a complex with PGRL1 (DalCorso et al, 2008), whereas in cyanobacteria, PGRL1 homologues are absent (Labs et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Enhanced Production of D-Lactate in Cyanobacteria by Re-Routing Photosynthetic Cyclic and Pseudo-Cyclic Electron Flow

et al. 2020

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Cyanobacteria are promising chassis strains for the photosynthetic production of platform and specialty chemicals from carbon dioxide. Their efficient light harvesting and metabolic flexibility abilities have allowed a wide range of biomolecules, such as the bioplastic polylactate precursor D-lactate, to be produced, though usually at relatively low yields. In order to increase photosynthetic electron flow towards the production of D-lactate, we have generated several strains of the marine cyanobacterium Synechococcus sp. PCC 7002 (Syn7002) with deletions in genes involved in cyclic or pseudo-cyclic electron flow around photosystem I. Using a variant of the Chlamydomonas reinhardtii D-lactate dehydrogenase (LDH SRT , engineered to efficiently utilize NADPH in vivo), we have shown that deletion of either of the two flavodiiron flv homologs (involved in pseudocyclic electron transport) or the Syn7002 pgr5 homolog (proposed to be a vital part of the cyclic electron transport pathway) is able to increase D-lactate production in Syn7002 strains expressing LDH SRT and the Escherichia coli LldP (lactate permease), especially at low temperature (25°C) and 0.04% (v/v) CO 2 , though at elevated temperatures (38°C) and/or high (1%) CO 2 concentrations, the effect was less obvious. The Dpgr5 background seemed to be particularly beneficial at 25°C and 0.04% (v/v) CO 2 , with a nearly 7-fold increase in D-lactate accumulation in comparison to the wild-type background (≈1000 vs ≈150 mg/L) and decreased side effects in comparison to the flv deletion strains. Overall, our results show that manipulation of photosynthetic electron flow is a viable strategy to increase production of platform chemicals in cyanobacteria under ambient conditions.

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Measurement of the redox state of the plastoquinone pool in cyanobacteria

et al. 2019

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Here, we developed a method for measuring the in vivo redox state of the plastoquinone (PQ) pool in the cyanobacteria Synechocystis sp. PCC 6803. Cells were illuminated on a glass fiber filter, PQ was extracted with ethyl acetate and determined with HPLC. Control samples with fully oxidized and reduced photoactive PQ pool were prepared by far-red and high light treatments, respectively, or by blocking the photosynthetic electron transfer chemically before or after PQ in moderate light. The photoactive pool comprised 50% of total PQ. We find that the PQ pool of cyanobacteria behaves under light treatments qualitatively similarly as in plant chloroplasts, is less reduced during growth under high than under ambient CO 2 and remains partly reduced in darkness.

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Structural adaptations of photosynthetic complex I enable ferredoxin-dependent electron transfer

Cited by 176 publications

References 87 publications

Redox-coupled proton pumping drives carbon concentration in the photosynthetic complex I

Redox-coupled proton pumping drives carbon concentration in the photosynthetic complex I

Enhanced Production of D-Lactate in Cyanobacteria by Re-Routing Photosynthetic Cyclic and Pseudo-Cyclic Electron Flow

Measurement of the redox state of the plastoquinone pool in cyanobacteria

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