Ferredoxin: the central hub connecting photosystem I to cellular metabolism

Mondal, Jyotirmoy; Bruce, Barry D.

doi:10.1007/s11099-018-0793-9

Cited by 28 publications

(26 citation statements)

References 117 publications

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“…Electron transfer then proceeds to the A 1A and A 1B cofactors within ∼ 30-50 ps (Brettel, 1997;Itoh et al, 2001), and then within 20 or 200 ns, respectively (Agalarov and Brettel, 2003;Kurashov et al, 2018) to the inter-polypeptide [4Fe-4S] cluster, F X , where the A-and B-branches are known to converge (Figure 4B). Subsequently, electron transfer occurs linearly though the F A and then F B clusters (Díaz-Quintana et al, 1998) with a lifetime of ∼ 200 ns, after which the electron is transferred to a soluble electron acceptor, ferredoxin (Mondal and Bruce, 2018) or flavodoxin (Pierella Karlusich and Carrillo, 2017), for downstream processes. For a detailed analysis of the electron-transfer and charge-recombination lifetimes in PS I, please see (Kurashov et al, 2018).…”

Section: Geometric Structures Geometric Structure Of the Primary Donor Of Heterodimeric Reaction Centersmentioning

confidence: 99%

Shedding Light on Primary Donors in Photosynthetic Reaction Centers

et al. 2021

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Chlorophylls (Chl)s exist in a variety of flavors and are ubiquitous in both the energy and electron transfer processes of photosynthesis. The functions they perform often occur on the ultrafast (fs–ns) time scale and until recently, these have been difficult to measure in real time. Further, the complexity of the binding pockets and the resulting protein-matrix effects that alter the respective electronic properties have rendered theoretical modeling of these states difficult. Recent advances in experimental methodology, computational modeling, and emergence of new reaction center (RC) structures have renewed interest in these processes and allowed researchers to elucidate previously ambiguous functions of Chls and related pheophytins. This is complemented by a wealth of experimental data obtained from decades of prior research. Studying the electronic properties of Chl molecules has advanced our understanding of both the nature of the primary charge separation and subsequent electron transfer processes of RCs. In this review, we examine the structures of primary electron donors in Type I and Type II RCs in relation to the vast body of spectroscopic research that has been performed on them to date. Further, we present density functional theory calculations on each oxidized primary donor to study both their electronic properties and our ability to model experimental spectroscopic data. This allows us to directly compare the electronic properties of hetero- and homodimeric RCs.

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Section: Geometric Structures Geometric Structure Of the Primary Donor Of Heterodimeric Reaction Centersmentioning

confidence: 99%

Shedding Light on Primary Donors in Photosynthetic Reaction Centers

et al. 2021

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“…Distances: MnComplex to water [29]; Qb and Qc near PQ binding site [30]; PS II [31] Cyt. b 6 f [32], PS I [33]; Fd & FNR [34]. Redox potentials: [11,35].…”

Section: Can the Z-scheme Fit Into A Viable Thermodynamic And Kinetic Purview?mentioning

confidence: 99%

Assessing the operational feasibility of ‘Z-scheme electron transport chain’ in chloroplasts

Manoj¹,

Gideon²,

Jacob³

et al. 2020

Preprint

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Z-scheme is a spatio-temporally demarcated, sequential/serial and vitally deterministic purview of ‘electron transport chain’, purportedly explaining the light reaction of oxygenic photosynthesis. Herein, first, we summarize the salient components of Z-scheme: Kok-Joliot cycle, P680 cycle, Q-cycle, plastocyanin relay, P700 cycle, ferredoxin relay and finally, NADPH synthesis by the flavin reductase. Then, a skeptic inquiry into the functioning of the component cycles and their integral functionality is carried out with respect to the following criteria: available structural information on chloroplast and relevant redox proteins, thermodynamics foundations, kinetics frameworks, evolutionary principles, and probability considerations. Since the Z-scheme fails to reason fundamental theoretical premises and several reported observations by various research groups over the last few decades, we infer that it cannot serve as a viable physiological logic for photosynthetic processes within chloroplasts.

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“…These E/D residues are not present on the surface of Fd at the same positions or surfaces either. Chloroplast Fds have been known to interact with diverse proteins like-hydrogenase (HydA1/2), bilin reductases, FTR, glutamate synthase, sulphite reductase, nitrate reductase, nitrite reductase, PS I and FNR (38). This probably makes Fd one of the most promiscuous redox proteins and such a protein with diverse partners surely must have different surface aminoacid residues/binding sites.…”

Section: Structural Aspects Required For Donor-acceptor Recognition and Bindingmentioning

confidence: 99%

Are plastocyanin and ferredoxin specific electron carriers or generic redox capacitors? Classical and murburn perspectives on two chloroplast proteins

Gideon¹,

Nirusimhan²,

Manoj³

2020

Preprint

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Within the context of light reaction of photosynthesis, the structure-function correlations of the chloroplast proteins of plastocyanin and ferredoxins (Fd) are analyzed via two perspectives: 1) The Z-scheme, which considers PC/Fd as specific affinity binding-based electron-relay agents, thereby deterministically linking the functions of Cytochrome b6f (Cyt. b6f) and Photosystem I (PS I) to NADP+ reduction by Fd:NADPH oxidoreductase (FNR) via protein-protein contacts and 2) The murburn explanation for oxygenic photophosphorylation, which deems PC/Fd as generic ‘redox capacitors’, temporally accepting and releasing one-electron equivalents in reaction milieu. Amino acid residues located on the surface loci of key patches of PC/Fd vary in electrostatic/contour (topography) signatures. Crystal structures of four different complexes each of cyt.f-PC and Fd-FNR show little conservation in the contact-surfaces, thereby discrediting ‘affinity binding-based electron transfers (ET)’ as an evolutionary logic. Further, thermodynamic and kinetic data on wildtype and mutant proteins interactions do not align well with model 1. Furthermore, micromolar physiological concentrations of PC (when Kd values 100 μM) and the non-conducive architecture of chloroplasts render the classical model untenable. In the 2nd model, PC is optional and higher concentrations of PC (sought by model 1) could inhibit ET, quite like the role of cytochrome c of mitochondria and cytochrome b5 of cytoplasmic microsomes. Also, PC is found in both lumen and stroma, and plants lacking PC survive and grow. Thus, evidence from structure, interactive dynamics with redox partners and physiological implications of PC/Fd supports the murburn perspective that these proteins serve as generic redox-capacitors in chloroplasts.

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Ferredoxin: the central hub connecting photosystem I to cellular metabolism

Cited by 28 publications

References 117 publications

Shedding Light on Primary Donors in Photosynthetic Reaction Centers

Shedding Light on Primary Donors in Photosynthetic Reaction Centers

Assessing the operational feasibility of ‘Z-scheme electron transport chain’ in chloroplasts

Are plastocyanin and ferredoxin specific electron carriers or generic redox capacitors? Classical and murburn perspectives on two chloroplast proteins

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