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Gorka M, Golbeck JH. Generating dihydrogen by tethering an [FeFe]hydrogenase via a molecular wire to the A 1A/A 1B sites of photosystem I. PHOTOSYNTHESIS RESEARCH 2020; 143:155-163. [PMID: 31673863 DOI: 10.1007/s11120-019-00685-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/15/2019] [Indexed: 06/10/2023]
Abstract
Photosystem I complexes from the menB deletion mutant of Synechocystis sp. PCC 6803 were previously wired to a Pt nanoparticle via a molecular wire consisting of 15-(3-methyl-1,4-naphthoquinone-2-yl)]pentadecyl sulfide. In the presence of a sacrificial electron donor and an electron transport mediator, the PS I-NQ(CH2)15S-Pt nanoconstruct generated dihydrogen at a rate of 44.3 µmol of H2 mg Chl-1 h-1 during illumination at pH 8.3. The menB deletion strain contains an interruption in the biosynthetic pathway of phylloquinone, which results in the presence of a displaceable plastoquinone-9 in the A1A/A1B sites. The synthesized quinone contains a headgroup identical to the native phylloquinone along with a 15-carbon long tail that is terminated in a thiol. The thiol on the molecular wire is used to bind the Pt nanoparticle. In this short communication, we replaced the Pt nanoparticle with an [FeFe]H2ase variant from Clostridium acetobutylicum that contains an exposed iron on the distal [4Fe-4S] cluster afforded by mutating the surface exposed Cys97 residue to Gly. The thiol on the molecular wire is then used to coordinate the corner iron atom of the iron-sulfur cluster. When all three components are combined and illuminated in the presence of a sacrificial electron donor and an electron transport mediator, the PS I-NQ(CH2)15S-[FeFe]H2ase nanoconstruct generated dihydrogen at a rate of 50.3 ± 9.96 μmol of H2 mg Chl-1 h-1 during illumination at pH 8.3. This successful in vitro experiment sets the stage for assembling a PS I-NQ(CH2)15S-[FeFe]H2ase nanoconstruct in vivo in the menB mutant of Synechocystis sp. PCC 6803.
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Affiliation(s)
- Michael Gorka
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S328 Frear Building, University Park, PA, 16802, USA.
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2
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Wittenberg G, Sheffler W, Darchi D, Baker D, Noy D. Accelerated electron transport from photosystem I to redox partners by covalently linked ferredoxin. Phys Chem Chem Phys 2013; 15:19608-14. [PMID: 24129892 DOI: 10.1039/c3cp53264j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photosystem I is a highly efficient and potent light-induced reductase that is considered to be an appealing target for integration into hybrid solar fuel production systems. However, rapid transport of multiple electrons from the reducing end of photosystem I to downstream processes in vivo is limited by the diffusion of its native redox partner ferredoxin that is a single electron carrier. Here, we describe the design and construction of a faster electron transfer interface based on anchoring ferredoxin to the reducing end of photosystem I thereby confining the diffusion space of ferredoxin to the near vicinity of its photosystem I binding and reduction site. This was achieved by fusing ferredoxin to the PsaE subunit of photosystem I by a flexible peptide linker and reconstituting PSI in vitro with the new fusion protein. A computational algorithm was developed in order to determine the optimal linker length that will confine ferredoxin to the vicinity of photosystem I's reducing end without restricting the formation of electron transfer complexes. According to the calculation, we reconstituted photosystem I with three fusion proteins comprising PsaE and ferredoxin separated by linkers of different lengths, namely 14, 19, and 25 amino acids, and tested their effect on electron transfer rates from photosystem I to downstream processes. Indeed, we found a significant enhancement of light dependent NADPH synthesis using photosystems containing the PsaE-ferredoxin fusion proteins, equivalent to a ten-fold increase in soluble ferredoxin concentration. We propose that such a system could be used for other ferredoxin dependent redox reactions, such as the enzymatic production of hydrogen, a promising alternative fuel. As the system is comprised entirely of natural amino acids and biological cofactors, it could be integrated into the energy conversion apparatus of photosynthetic organisms by genetic engineering.
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Affiliation(s)
- Gal Wittenberg
- Plant Sciences Department, Weizmann Institute of Science, Rehovot 7610001, Israel
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3
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Solar hydrogen-producing bionanodevice outperforms natural photosynthesis. Proc Natl Acad Sci U S A 2011; 108:20988-91. [PMID: 22160679 DOI: 10.1073/pnas.1114660108] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although a number of solar biohydrogen systems employing photosystem I (PSI) have been developed, few attain the electron transfer throughput of oxygenic photosynthesis. We have optimized a biological/organic nanoconstruct that directly tethers F(B), the terminal [4Fe-4S] cluster of PSI from Synechococcus sp. PCC 7002, to the distal [4Fe-4S] cluster of the [FeFe]-hydrogenase (H(2)ase) from Clostridium acetobutylicum. On illumination, the PSI-[FeFe]-H(2)ase nanoconstruct evolves H(2) at a rate of 2,200 ± 460 μmol mg chlorophyll(-1) h(-1), which is equivalent to 105 ± 22 e(-)PSI(-1) s(-1). Cyanobacteria evolve O(2) at a rate of approximately 400 μmol mg chlorophyll(-1) h(-1), which is equivalent to 47 e(-)PSI(-1) s(-1), given a PSI to photosystem II ratio of 1.8. The greater than twofold electron throughput by this hybrid biological/organic nanoconstruct over in vivo oxygenic photosynthesis validates the concept of tethering proteins through their redox cofactors to overcome diffusion-based rate limitations on electron transfer.
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Lubner CE, Knörzer P, Silva PJN, Vincent KA, Happe T, Bryant DA, Golbeck JH. Wiring an [FeFe]-hydrogenase with photosystem I for light-induced hydrogen production. Biochemistry 2010; 49:10264-6. [PMID: 21058656 DOI: 10.1021/bi1016167] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A molecular wire is used to connect two proteins through their physiologically relevant redox cofactors to facilitate direct electron transfer. Photosystem I (PS I) and an [FeFe]-hydrogenase (H(2)ase) serve as the test bed for this new technology. By tethering a photosensitizer with a hydrogen-evolving catalyst, attached by Fe-S coordination bonds between the F(B) iron-sulfur cluster of PS I and the distal iron-sulfur cluster of H(2)ase, we assayed electron transfer between the two components via light-induced hydrogen generation. These hydrogen-producing nanoconstructs self-assemble when the PS I variant, the H(2)ase variant, and the molecular wire are combined.
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Affiliation(s)
- Carolyn E Lubner
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
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Lubner CE, Grimme R, Bryant DA, Golbeck JH. Wiring photosystem I for direct solar hydrogen production. Biochemistry 2010; 49:404-14. [PMID: 19947649 DOI: 10.1021/bi901704v] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The generation of H(2) by the use of solar energy is a promising way to supply humankind's energy needs while simultaneously mitigating environmental concerns that arise due to climate change. The challenge is to find a way to connect a photochemical module that harnesses the sun's energy to a catalytic module that generates H(2) with high quantum yields and rates. In this review, we describe a technology that employs a "molecular wire" to connect a terminal [4Fe-4S] cluster of Photosystem I directly to a catalyst, which can be either a Pt nanoparticle or the distal [4Fe-4S] cluster of an [FeFe]- or [NiFe]-hydrogenase enzyme. The keys to connecting these two moieties are surface-located cysteine residues, which serve as ligands to Fe-S clusters and which can be changed through site-specific mutagenesis to glycine residues, and the use of a molecular wire terminated in sulfhydryl groups to connect the two modules. The sulfhydryl groups at the end of the molecular wire form a direct chemical linkage to a suitable catalyst or can chemically rescue a [4Fe-4S] cluster, thereby generating a strong coordination bond. Specifically, the molecular wire can connect the F(B) iron-sulfur cluster of Photosystem I either to a Pt nanoparticle or, by using the same type of genetic modification, to the differentiated iron atom of the distal [4Fe-4S].(Cys)(3)(Gly) cluster of hydrogenase. When electrons are supplied by a sacrificial donor, this technology forms the cathode of a photochemical half-cell that evolves H(2) when illuminated. If such a device were connected to the anode of a photochemical half-cell that oxidizes water, an in vitro solar energy converter could be realized that generates only O(2) and H(2) in the light. A similar methodology can be used to connect Photosystem I to other redox proteins that have surface-located [4Fe-4S] clusters. The controlled light-driven production of strong reductants by such systems can be used to produce other biofuels or to provide mechanistic insights into enzymes catalyzing multielectron, proton-coupled reactions.
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Affiliation(s)
- Carolyn E Lubner
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Jin Z, Heinnickel M, Krebs C, Shen G, Golbeck JH, Bryant DA. Biogenesis of iron-sulfur clusters in photosystem I: holo-NfuA from the cyanobacterium Synechococcus sp. PCC 7002 rapidly and efficiently transfers [4Fe-4S] clusters to apo-PsaC in vitro. J Biol Chem 2008; 283:28426-35. [PMID: 18694929 DOI: 10.1074/jbc.m803395200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The NfuA protein has been postulated to act as a scaffolding protein in the biogenesis of photosystem (PS) I and other iron-sulfur (Fe/S) proteins in cyanobacteria and chloroplasts. To determine the properties of NfuA, recombinant NfuA from Synechococcus sp. PCC 7002 was overproduced and purified. In vitro reconstituted NfuA contained oxygen- and EDTA-labile Fe/S cluster(s), which had EPR properties consistent with [4Fe-4S] clusters. After reconstitution with 57Fe2+, Mössbauer studies of NfuA showed a broad quadrupole doublet that confirmed the presence of [4Fe-4S]2+ clusters. Native gel electrophoresis under anoxic conditions and chemical cross-linking showed that holo-NfuA forms dimers and tetramers harboring Fe/S cluster(s). Combined with iron and sulfide analyses, the results indicated that one [4Fe-4S] cluster was bound per NfuA dimer. Fe/S cluster transfer from holo-NfuA to apo-PsaC of PS I was studied by reconstitution of PS I complexes using P700-F(X) core complexes, PsaD, apo-PsaC, and holo-NfuA. Electron transfer measurements by time-resolved optical spectroscopy showed that holo-NfuA rapidly and efficiently transferred [4Fe-4S] clusters to PsaC in a reaction that required contact between the two proteins. The NfuA-reconstituted PS I complexes had typical charge recombination kinetics from [F(A)/F(B)](-) to P700+ and light-induced low-temperature EPR spectra. These results establish that cyanobacterial NfuA can act as a scaffolding protein for the insertion of [4Fe-4S] clusters into PsaC of PS I in vitro.
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Affiliation(s)
- Zhao Jin
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Vassiliev IR, Antonkine ML, Golbeck JH. Iron-sulfur clusters in type I reaction centers. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1507:139-60. [PMID: 11687212 DOI: 10.1016/s0005-2728(01)00197-9] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Type I reaction centers (RCs) are multisubunit chlorophyll-protein complexes that function in photosynthetic organisms to convert photons to Gibbs free energy. The unique feature of Type I RCs is the presence of iron-sulfur clusters as electron transfer cofactors. Photosystem I (PS I) of oxygenic phototrophs is the best-studied Type I RC. It is comprised of an interpolypeptide [4Fe-4S] cluster, F(X), that bridges the PsaA and PsaB subunits, and two terminal [4Fe-4S] clusters, F(A) and F(B), that are bound to the PsaC subunit. In this review, we provide an update on the structure and function of the bound iron-sulfur clusters in Type I RCs. The first new development in this area is the identification of F(A) as the cluster proximal to F(X) and the resolution of the electron transfer sequence as F(X)-->F(A)-->F(B)-->soluble ferredoxin. The second new development is the determination of the three-dimensional NMR solution structure of unbound PsaC and localization of the equal- and mixed-valence pairs in F(A)(-) and F(B)(-). We provide a survey of the EPR properties and spectra of the iron-sulfur clusters in Type I RCs of cyanobacteria, green sulfur bacteria, and heliobacteria, and we summarize new information about the kinetics of back-reactions involving the iron-sulfur clusters.
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Affiliation(s)
- I R Vassiliev
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 310 South Frear Building, University Park, PA 16802, USA
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[7] Comparison of in Vitro and in Vivo mutants of PsaC in photosystem I: Protocols for mutagenesis and techniques for analysis. Methods Enzymol 1998. [DOI: 10.1016/s0076-6879(98)97009-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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9
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Rodday SM, Do LT, Chynwat V, Frank HA, Biggins J. Site-directed mutagenesis of the subunit PsaC establishes a surface-exposed domain interacting with the photosystem I core binding site. Biochemistry 1996; 35:11832-8. [PMID: 8794765 DOI: 10.1021/bi9612834] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We have postulated that the orientation of PsaC on the photosystem I core involves electrostatic interactions between charged residues on the core binding site and the subunit [Rodday, S. M., Jun, S.-S., & Biggins, J. (1993) Photosynth. Res. 36, 1-9]. We, therefore, changed eight acidic residues on PsaC to arginine and examined the efficiency of the mutant subunits in the reconstitution of P700-Fx cores in vitro. Reconstitution of the cores by the mutant subunits was determined by analysis of the kinetics of recombination reactions between P700+ and reduced acceptors as measured optically. Restoration of complete forward electron transfer, indicative of efficient subunit binding, was estimated from the ca. 30 ms decay component in the flash transients. Slightly reduced levels of reconstitution were observed for the mutants D24R, E46R/D47R. D61R, and E72R. In contrast, mutants D9R, E27R, and D32R showed significantly lower efficiencies. The presence of the iron-sulfur centers, FA and FB, in these three mutant subunits was confirmed by low-temperature EPR spectroscopy indicating that the polypeptides had folded correctly. We conclude that the introduction of positively charged side chains at positions 9, 27, and 32 seriously disrupts PsaC binding. However, when the wild-type acidic residues in these positions were changed to alanine, only mutant D9A showed a reduced level of reconstitution, suggesting that this aspartate is the most important residue participating in the electrostatic interaction with the core. The results are discussed in relation to the photosystem I crystal structure and support an orientation of PsaC on the core such that center FB is proximal to Fx.
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Affiliation(s)
- S M Rodday
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, Rhode Island 02912, USA
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10
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Nechushtai R, Cohen Y, Chitnis PR. Assembly of the chlorophyll-protein complexes. PHOTOSYNTHESIS RESEARCH 1995; 44:165-181. [PMID: 24307036 DOI: 10.1007/bf00018307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/1994] [Accepted: 03/10/1995] [Indexed: 06/02/2023]
Abstract
The biogenesis of photosynthetic complexes in plants and algae is a multi-step process that involves intricate coordination of steps in two intracellular compartments, the chloroplast and the cytoplasm. The process initiates with the transcription and translation of the various polypeptide subunits. The nuclear-encoded Chl-binding proteins are translated on cytoplasmic ribosomes as precursors that have a transit (leader) sequence at their amino-terminus. The precursors are post-translationally imported into the chloroplasts, proteolytically processed into their mature forms, inserted into the thylationally imported into the chloroplasts, proteolytically processed into their mature forms, inserted into the thylakoid membrane, and bound to their co-factors (and pigments) and with other subunits to form an active complex. The order and mechanisms by which these events occur, are currently being discovered. Electrostatic interactions, the 'positive inside rule', interhelix interactions, interactions with lipids and chaperone proteins affect the insertion and stabilization of the Chl-proteins in the thylakoids. This review describes the events occurring during the integration and organization of the Chl-proteins.
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Affiliation(s)
- R Nechushtai
- Department of Botany, The Hebrew University of Jerusalem, 91904, Jerusalem, Israel
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11
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Chitnis PR, Xu Q, Chitnis VP, Nechushtai R. Function and organization of Photosystem I polypeptides. PHOTOSYNTHESIS RESEARCH 1995; 44:23-40. [PMID: 24307023 DOI: 10.1007/bf00018294] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/1994] [Accepted: 12/27/1994] [Indexed: 06/02/2023]
Abstract
Photosystem I functions as a plastocyanin:ferredoxin oxidoreductase in the thylakoid membranes of chloroplasts and cyanobacteria. The PS I complex contains the photosynthetic pigments, the reaction center P700, and five electron transfer centers (A0, A1, FX, FA, and FB) that are bound to the PsaA, PsaB, and PsaC proteins. In addition, PS I complex contains at least eight other polypeptides that are accessory in their functions. Recent use of cyanobacterial molecular genetics has revealed functions of the accessory subunits of PS I. Site-directed mutagenesis is now being used to explore structure-function relations in PS I. The overall architecture of PSI complex has been revealed by X-ray crystallography, electron microscopy, and biochemical methods. The information obtained by different techniques can be used to propose a model for the organization of PS I. Spectroscopic and molecular genetic techniques have deciphered interaction of PS I proteins with the soluble electron transfer partners. This review focuses on the recent structural, biochemical and molecular genetic studies that decipher topology and functions of PS I proteins, and their interactions with soluble electron carriers.
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Affiliation(s)
- P R Chitnis
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
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12
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Rodday SM, Schulz R, McLntosh L, Biggins J. Structure-function studies on the interaction of PsaC with the Photosystem 1 heterodimer : The site directed change R561E in PsaB destabilizes the subunit interaction in Synechocystis sp. PCC 6803. PHOTOSYNTHESIS RESEARCH 1994; 42:185-190. [PMID: 24306560 DOI: 10.1007/bf00018261] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/1994] [Accepted: 09/29/1994] [Indexed: 06/02/2023]
Abstract
The interaction of PsaC with the core heterodimer of Photosystem 1 was studied in wild type Synechocystis sp. PCC 6803 and the site-directed mutant R561E of PsaB. The mutant reaction center was much less stable in urea and the functional reconstitution of the mutant core using PsaC was impaired. However, the extent of reconstitution increased in the presence of divalent cations whereas that of the wild type was inhibited. We conclude that the reaction center in the mutant is unstable, most likely due to the introduction of an unfavorable electrostatic interaction between surface-exposed residues on PsaC and the binding site for the subunit on the core heterodimer in support of the model proposed previously (Rodday et al. (1993) Photosynth Res 36: 1-9).
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Affiliation(s)
- S M Rodday
- Section of Biochemistry, Brown University, 02912, Providence, RI, USA
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Kleinherenbrink FA, Chiou HC, LoBrutto R, Blankenship RE. Spectroscopic evidence for the presence of an iron-sulfur center similar to Fx of Photosystem I in Heliobacillus mobilis. PHOTOSYNTHESIS RESEARCH 1994; 41:115-123. [PMID: 11539856 DOI: 10.1007/bf02184151] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Treatment of membranes of Heliobacillus mobilis with high concentrations of the chaotropic agent urea resulted in the removal of the iron-sulfur centers FA and FB from the reaction center, as indicated by EPR spectra under strongly reducing conditions. In urea-treated membranes, transient absorption measurements upon a laser flash indicated a recombination between the photo-oxidized primary donor P798+ and a reduced acceptor with a time constant of 20 ms at room temperature. Benzylviologen, vitamin K-3 and methylene blue were found to accept electrons from the reduced acceptor efficiently. A differential extinction coefficient of 225-240 mM-1 cm-1 at 798 nm was determined from experiments in the presence of methylene blue. Transient absorption difference spectra between 400 and 500 nm in the presence and absence of artificial acceptors indicated that the electron acceptor involved in the 20 ms recombination has an absorption spectrum similar to that of an iron-sulfur center. This iron-sulfur center was assigned to be analogous to Fx of Photosystem I. Our results provide evidence in support of the presence of Fx in heliobacteria, which was proposed on the basis of the reaction center polypeptide sequence (Liebl et al. (1993) Proc. Natl. Acad. Sci. USA 90: 7124-7128). Implications for the electron transfer pathway in the reaction center of heliobacteria are discussed.
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Affiliation(s)
- F A Kleinherenbrink
- Department of Chemistry and Biochemistry, Arizona State University, Tempe 85287-1604, USA
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14
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Lüneberg J, Fromme P, Jekow P, Schlodder E. Spectroscopic characterization of PS I core complexes from thermophilic Synechococcus sp. Identical reoxidation kinetics of A1- before and after removal of the iron-sulfur-clusters FA and FB. FEBS Lett 1994; 338:197-202. [PMID: 8307180 DOI: 10.1016/0014-5793(94)80364-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Monomeric and trimeric PS I complexes missing the three stromal subunits E,C and D (termed PS I core complexes) were prepared from the thermophilic cyanobacterium Synechococcus sp. by incubation with urea. The subunits E,C and D are sequentially removed. In the monomeric PS I the subunit C is removed with a half life of approx. 5 min. This is about eight times faster than in the trimeric PS I complex. In parallel with the removal of the FA/B containing subunit C the reduction kinetics of P700+ changed from a half life of about 25 ms to about 750 microseconds. The partner of P700+ in the 750 microseconds charge recombination was identified to be FX by the difference spectrum of this phase. There are some minor differences in the spectra of trimeric and monomeric PS I core complexes. At 77K the forward electron transfer from A1- to FX is blocked in the major fraction of the PS I core complexes and P700+ A1- recombines with a half life of about 220 microseconds. In the remaining fraction P700+FX- is formed and decays with a half life of approx. 10 ms at 77 K. The kinetics of the forward electron transfer from A1- to the iron-sulfur-clusters was measured in the native PS I and the corresponding core complexes. The reoxidation kinetics of A1- are identical in both cases (t1/2 = 180 ns). We conclude that FX is an obligatory intermediate in the normal forward electron transfer.
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Affiliation(s)
- J Lüneberg
- Max-Volmer-Institut für Biophysikalische und Physikalische Chemie, Technische Universität Berlin, Germany
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Kruip J, Boekema E, Bald D, Boonstra A, Rögner M. Isolation and structural characterization of monomeric and trimeric photosystem I complexes (P700.FA/FB and P700.FX) from the cyanobacterium Synechocystis PCC 6803. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)49470-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Rodday SM, Jun SS, Biggins J. Interaction of the FAF B-containing subunit with the Photosystem 1 core heterodimer. PHOTOSYNTHESIS RESEARCH 1993; 36:1-9. [PMID: 24318792 DOI: 10.1007/bf00018069] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/1992] [Accepted: 11/06/1992] [Indexed: 06/02/2023]
Abstract
The structure of the predicted amino acid sequence in the FX domain of Photosystem 1 was studied by molecular modeling and a working hypothesis was developed for the functional interaction of PsaC with the core heterodimer. We propose that the intervening sequences between homologous cysteines in the FX cluster form two flexible loops and participate in the binding of PsaC, and that the arginine residues in the two surface-exposed loops may promote the interaction between the P700-FX core and the subunit. The model was tested experimentally; chemical modification of arginine residues in the P700-FX core using phenylglyoxal prevented reconstitution of the core with PsaC and PsaD after insertion of FeS clusters in vitro. Treatment of the P700-FX core with trypsin also prevented reconstitution of terminal electron transfer to FAFB, although neither treatments affected the electron transfer to FX as judged by flash kinetic spectrophotometry. Electron transfer in the P700-FAFB complex was not impaired by either phenylglyoxal or trypsin treatment indicating that the small subunit(s) protect the arginine residues that become chemically modified or cleaved. The data are consistent with the working model and point to additional experiments designed to identify the specific residues involved in the interaction between the P700-FX core and PsaC.
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Affiliation(s)
- S M Rodday
- Section of Biochemistry, Brown University, 02912, Providence, RI, USA
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17
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Hanley J, Kear J, Bredenkamp G, Li G, Heathcote P, Evans M. Biochemical evidence for the role of the bound iron-sulphur centres A and B in NADP reduction by Photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1992. [DOI: 10.1016/0005-2728(92)90212-k] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Matsubara H, Saeki K. Structural and Functional Diversity of Ferredoxins and Related Proteins. ADVANCES IN INORGANIC CHEMISTRY 1992. [DOI: 10.1016/s0898-8838(08)60065-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Chitnis P, Purvis D, Nelson N. Molecular cloning and targeted mutagenesis of the gene psaF encoding subunit III of photosystem I from the cyanobacterium Synechocystis sp. PCC 6803. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54902-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Li N, Warren PV, Golbeck JH, Frank G, Zuber H, Bryant DA. Polypeptide composition of the Photosystem I complex and the Photosystem I core protein from Synechococcus sp. PCC 6301. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1059:215-25. [PMID: 1653017 DOI: 10.1016/s0005-2728(05)80206-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The polypeptide composition of the Photosystem I complex from Synechococcus sp. PCC 6301 was determined by sodium-dodecyl sulfate polyacrylamide gel electrophoresis and N-terminal amino acid sequencing. The PsaA, PsaB, PsaC, PsaD, PsaE, PsaF, PsaK and PsaL proteins, as well as three polypeptides with apparent masses less than 8 kDa and small amounts of the 12.6 kDa GlnB (PII) protein, wee present in the Photosystem I complex. No proteins homologous to the PsaG and PsaH subunits of eukaryotic Photosystem I complexes were detected. When the Photosystem I complex was treated with 6.8 M urea and ultrafiltered using a 100 kDa cutoff membrane, the resulting Photosystem I core protein was found to be depleted of the PsaC, PsaD and PsaE proteins. The filtrate contained the missing proteins, along with five proteolytically-cleaved polypeptides with apparent masses of less than 16 kDa and with N-termini identical to that of the PsaD protein. The PsaF and PsaL proteins, along with the three less than 8 kDa polypeptides, were not released from the Photosystem I complex to any significant extent, but low-abundance polypeptides with N-termini identical to those of PsaF and PsaL were found in the filtrate with apparent masses slightly smaller than those found in the native Photosystem I complex. When the filtrate was incubated with FeCl3, Na2S and beta-mercaptoethanol in the presence of the isolated Photosystem I core protein, the PsaC, PsaD and PsaE proteins were rebound to reconstitute a Photosystem I complex functional in light-induced electron flow from P700 to FA/FB. In the absence of the iron-sulfur reconstitution agents, there was little rebinding of the PsaC, psaD or PsaE proteins to the Photosystem I core protein. No binding of the truncated PsaD polypeptides occurred, either in the presence or absence of the iron-sulfur reagents. The reconstitution of the FA/FB iron-sulfur clusters thus appears to be a necessary precondition for rebinding of the PsaC, psaD and psaE proteins to the Photosystem I core protein.
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Affiliation(s)
- N Li
- Department of Biochemistry, University of Nebraska, Lincoln
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Li N, Zhao JD, Warren PV, Warden JT, Bryant DA, Golbeck JH. PsaD is required for the stable binding of PsaC to the photosystem I core protein of Synechococcus sp. PCC 6301. Biochemistry 1991; 30:7863-72. [PMID: 1651109 DOI: 10.1021/bi00245a028] [Citation(s) in RCA: 145] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The psaC gene product from Synechococcus sp. PCC 7002 and the psaD gene product from Nostoc sp. PCC 8009 were synthesized in Escherichia coli and purified to homogeneity. Incubation of the PsaC apoprotein with the Synechoccus sp. PCC 6301 photosystem I core protein in the presence of FeCl3, Na2S, and beta-mercaptoethanol resulted in a time-dependent transition in the flash-induced absorption change from a 1.2-ms, P700+ FX- back-reaction to a long-lived, P700+ [FA/FB]- back-reaction. ESR studies showed that FB and FA were photoreduced about equally at 19 K, and while the resonances were shifted upfield, they remained as broad as in the free PsaC holoprotein. When the reconstituted complex was purified in a sucrose gradient containing 0.1% Triton X-100, most of the optical absorption transient reverted to that characteristic of the P700+ FX- back-reaction. Addition of purified PsaD to the incubation mixture led to a greater extent of recovery of electron flow to FA/FB for any given concentration of PsaC. ESR studies showed that FA, rather than FB, became the preferred electron acceptor at 19 K; moreover, the resonances moved upfield and sharpened to become nearly identical with those of a control photosystem I complex. When the sample was purified in a sucrose gradient containing 0.1% Triton X-100, the long-lived P700+ [FA/FB]- optical transient remained stable. Analysis by denaturing polyacrylamide gel electrophoresis showed that the PsaC and PsaD proteins had rebound to the photosystem I core. The data indicate that although PsaC can bind loosely, the presence of PsaD leads to a stable, isolatable photosystem I complex which is spectroscopically indistinguishable from the native complex. Since a PsaC1 fusion protein which contains an amino-terminal extension of five amino acids (MEHSM...) does not bind in the absence of PsaD [Zhao, J., et al. (1990) FEBS Lett. 276, 175-180], the N-terminus of the PsaC protein could provide a site of interaction with the photosystem I core. We propose that the binding of PsaC to the PsaA/PsaB heterodimer is potentiated by insertion of the FA/FB clusters into PsaC, and stabilized by the presence of PsaD.
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Affiliation(s)
- N Li
- Department of Biochemistry, University of Nebraska, Lincoln 68583-0718
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Knaff DB, Hirasawa M. Ferredoxin-dependent chloroplast enzymes. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1056:93-125. [PMID: 1671559 DOI: 10.1016/s0005-2728(05)80277-4] [Citation(s) in RCA: 198] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- D B Knaff
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409-1061
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Reconstitution of the iron-sulfur clusters in the isolated FA/FB protein: EPR spectral characterization of same-species and cross-species Photosystem I complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1991. [DOI: 10.1016/s0005-2728(05)80280-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Purification and characterization of photosystem I and photosystem II core complexes from wild-type and phycocyanin-deficient strains of the cyanobacterium Synechocystis PCC 6803. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39309-3] [Citation(s) in RCA: 189] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Cook WB, Miles D. Anomalous electron transport activity in a Photosystem I-deficient maize mutant. PHOTOSYNTHESIS RESEARCH 1990; 24:81-8. [PMID: 24419768 DOI: 10.1007/bf00032647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/1989] [Accepted: 10/23/1989] [Indexed: 05/10/2023]
Abstract
Photosynthesis mutations were induced in maize lines bearing the transposable DNA element system, Mutator. Two Photosystem I mutants (hcf101 and hcf104) which were isolated are described here. Maize plants homozygous for the hcf104 mutation are seedling lethal and exhibit a high in vivo chlorophyll fluorescence yield. They lack ∼60% of CP1, P700 and PSI-specific electron transport activity relative to normal sibling plants. The comparable depletion of these three measures of PS I content conforms to the pattern reported for many other PS I-deficient mutants. Maize plants homozygous for hcf101 are seedling lethal and also exhibit high in vivo chlorophyll fluorescence yield. They lack 80-90% of CP1 and P700 but sustain steady state levels of PS I-specific electron transport activity at 70% of normal. Previous reports of similar apparent PS I hyperactivity are discussed and an explanation for the elevated steady state level of PS I electron transport activity in hcf101 is proposed.
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Affiliation(s)
- W B Cook
- Department of Biological Sciences, University of Missouri, 65211, Columbia, MO, USA
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Resolution and reconstitution of the cyanobacterial photosystem I complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1990. [DOI: 10.1016/0005-2728(90)90039-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Hoshina S, Sakurai R, Kunishima N, Wada K, Itoh S. Selective destruction of iron-sulfur centers by heat/ethylene glycol treatment and isolation of Photosystem I core complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1990. [DOI: 10.1016/0005-2728(90)90216-q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Chitnis PR, Reilly PA, Miedel MC, Nelson N. Structure and targeted mutagenesis of the gene encoding 8-kDa subunit of photosystem I from the cyanobacterium Synechocystis sp. PCC 6803. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)51474-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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