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International Journal of Molecular... Jan 2023Eukaryotic photosynthesis originated in the course of evolution as a result of the uptake of some unstored cyanobacterium and its transformation to chloroplasts by an... (Review)
Review
Eukaryotic photosynthesis originated in the course of evolution as a result of the uptake of some unstored cyanobacterium and its transformation to chloroplasts by an ancestral heterotrophic eukaryotic cell. The pigment apparatus of Archaeplastida and other algal phyla that emerged later turned out to be arranged in the same way. Pigment-protein complexes of photosystem I (PS I) and photosystem II (PS II) are characterized by uniform structures, while the light-harvesting antennae have undergone a series of changes. The phycobilisome (PBS) antenna present in cyanobacteria was replaced by Chl - or Chl -containing pigment-protein complexes in most groups of photosynthetics. In the form of PBS or phycobiliprotein aggregates, it was inherited by members of Cyanophyta, Cryptophyta, red algae, and photosynthetic amoebae. Supramolecular organization and architectural modifications of phycobiliprotein antennae in various algal phyla in line with the endosymbiotic theory of chloroplast origin are the subject of this review.
Topics: Phycobilisomes; Phycobiliproteins; Symbiosis; Oxygen; Photosynthesis; Cyanobacteria; Photosystem II Protein Complex; Photosystem I Protein Complex; Chlorophyll
PubMed: 36768613
DOI: 10.3390/ijms24032290 -
Toxics Jun 2022Heavy metals such as Cd pose environmental problems and threats to a variety of organisms. The effects of cadmium (Cd) on the growth and activities of photosystem I...
Heavy metals such as Cd pose environmental problems and threats to a variety of organisms. The effects of cadmium (Cd) on the growth and activities of photosystem I (PSI) and photosystem II (PSII) of Chlorella pyrenoidosa were studied. The growth rate of cells treated with 25 and 100 µM of Cd for longer than 48 h were significantly lower than the control, accompanying with the inhibition of photosynthesis. The result of quantum yields and electron transport rates (ETRs) in PSI and PSII showed that Cd had a more serious inhibition on PSII than on PSI. Cd decreased the efficiency of PSII to use the energy under high light with increasing Cd concentration. In contrast, the quantum yield of PSI did not show a significant difference among different Cd treatments. The activation of cyclic electron flow (CEF) and the inhibition of linear electron flow (LEF) due to Cd treatment were observed. The photochemical quantum yield of PSI and the tolerance of ETR of PSI to Cd treatments were due to the activation of CEF around PSI. The activation of CEF also played an important role in induction of non-photochemical quenching (NPQ). The binding features of Cd ions and photosystem particles showed that Cd was easier to combine with PSII than PSI, which may explain the different toxicity of Cd on PSII and PSI.
PubMed: 35878257
DOI: 10.3390/toxics10070352 -
FEBS Letters Jan 2023The understanding of light-induced biological water oxidation in oxygenic photosynthesis is of great importance both for biology and (bio)technological applications. The... (Review)
Review
The understanding of light-induced biological water oxidation in oxygenic photosynthesis is of great importance both for biology and (bio)technological applications. The chemically difficult multistep reaction takes place at a unique protein-bound tetra-manganese/calcium cluster in photosystem II whose structure has been elucidated by X-ray crystallography (Umena et al. Nature 2011, 473, 55). The cluster moves through several intermediate states in the catalytic cycle. A detailed understanding of these intermediates requires information about the spatial and electronic structure of the Mn Ca complex; the latter is only available from spectroscopic techniques. Here, the important role of Electron Paramagnetic Resonance (EPR) and related double resonance techniques (ENDOR, EDNMR), complemented by quantum chemical calculations, is described. This has led to the elucidation of the cluster's redox and protonation states, the valence and spin states of the manganese ions and the interactions between them, and contributed substantially to the understanding of the role of the protein surrounding, as well as the binding and processing of the substrate water molecules, the O-O bond formation and dioxygen release. Based on these data, models for the water oxidation cycle are developed.
Topics: Water; Oxygen; Manganese; Oxidation-Reduction; Photosystem II Protein Complex; Electron Spin Resonance Spectroscopy; Photosynthesis
PubMed: 36409002
DOI: 10.1002/1873-3468.14543 -
ELife Sep 2022Two species of photosynthetic cyanobacteria can thrive in far-red light but they either become less resilient to photodamage or less energy efficient.
Two species of photosynthetic cyanobacteria can thrive in far-red light but they either become less resilient to photodamage or less energy efficient.
Topics: Cyanobacteria; Light; Photosynthesis; Photosystem I Protein Complex; Photosystem II Protein Complex
PubMed: 36053269
DOI: 10.7554/eLife.82221 -
International Journal of Molecular... May 2024Photosynthesis, as the primary source of energy for all life forms, plays a crucial role in maintaining the global balance of energy, entropy, and enthalpy in living... (Review)
Review
Photosynthesis, as the primary source of energy for all life forms, plays a crucial role in maintaining the global balance of energy, entropy, and enthalpy in living organisms. Among its various building blocks, photosystem I (PSI) is responsible for light-driven electron transfer, crucial for generating cellular reducing power. PSI acts as a light-driven plastocyanin-ferredoxin oxidoreductase and is situated in the thylakoid membranes of cyanobacteria and the chloroplasts of eukaryotic photosynthetic organisms. Comprehending the structure and function of the photosynthetic machinery is essential for understanding its mode of action. New insights are offered into the structure and function of PSI and its associated light-harvesting proteins, with a specific focus on the remarkable structural conservation of the core complex and high plasticity of the peripheral light-harvesting complexes.
Topics: Photosystem I Protein Complex; Photosynthesis; Light-Harvesting Protein Complexes; Cyanobacteria; Models, Molecular; Electron Transport
PubMed: 38791114
DOI: 10.3390/ijms25105073 -
The New Phytologist Nov 2020Photosystems I and II are the central components of the solar energy conversion machinery in oxygenic photosynthesis. They are large functional units embedded in the... (Review)
Review
Photosystems I and II are the central components of the solar energy conversion machinery in oxygenic photosynthesis. They are large functional units embedded in the photosynthetic membranes, where they harvest light and use its energy to drive electrons from water to NADPH. Their composition and organization change in response to different environmental conditions, making these complexes dynamic units. Some of the interactions between subunits survive purification, resulting in the well-defined structures that were recently resolved by cryo-electron microscopy. Other interactions instead are weak, preventing the possibility of isolating and thus studying these complexes in vitro. This review focuses on these supercomplexes of vascular plants, which at the moment cannot be 'seen' but that represent functional units in vivo.
Topics: Cryoelectron Microscopy; Electrons; Light-Harvesting Protein Complexes; Oxygen; Photosynthesis; Photosystem I Protein Complex; Photosystem II Protein Complex
PubMed: 32562266
DOI: 10.1111/nph.16758 -
Nature Communications Jun 2024Cryptophytes are ancestral photosynthetic organisms evolved from red algae through secondary endosymbiosis. They have developed alloxanthin-chlorophyll a/c2-binding...
Cryptophytes are ancestral photosynthetic organisms evolved from red algae through secondary endosymbiosis. They have developed alloxanthin-chlorophyll a/c2-binding proteins (ACPs) as light-harvesting complexes (LHCs). The distinctive properties of cryptophytes contribute to efficient oxygenic photosynthesis and underscore the evolutionary relationships of red-lineage plastids. Here we present the cryo-electron microscopy structure of the Photosystem II (PSII)-ACPII supercomplex from the cryptophyte Chroomonas placoidea. The structure includes a PSII dimer and twelve ACPII monomers forming four linear trimers. These trimers structurally resemble red algae LHCs and cryptophyte ACPI trimers that associate with Photosystem I (PSI), suggesting their close evolutionary links. We also determine a Chl a-binding subunit, Psb-γ, essential for stabilizing PSII-ACPII association. Furthermore, computational calculation provides insights into the excitation energy transfer pathways. Our study lays a solid structural foundation for understanding the light-energy capture and transfer in cryptophyte PSII-ACPII, evolutionary variations in PSII-LHCII, and the origin of red-lineage LHCIIs.
Topics: Photosystem II Protein Complex; Light-Harvesting Protein Complexes; Cryptophyta; Cryoelectron Microscopy; Photosynthesis; Models, Molecular; Energy Transfer; Photosystem I Protein Complex; Chlorophyll A
PubMed: 38866834
DOI: 10.1038/s41467-024-49453-0 -
Frontiers in Plant Science 2023The need to acclimate to different environmental conditions is central to the evolution of cyanobacteria. Far-red light (FRL) photoacclimation, or FaRLiP, is an...
The need to acclimate to different environmental conditions is central to the evolution of cyanobacteria. Far-red light (FRL) photoacclimation, or FaRLiP, is an acclimation mechanism that enables certain cyanobacteria to use FRL to drive photosynthesis. During this process, a well-defined gene cluster is upregulated, resulting in changes to the photosystems that allow them to absorb FRL to perform photochemistry. Because FaRLiP is widespread, and because it exemplifies cyanobacterial adaptation mechanisms in nature, it is of interest to understand its molecular evolution. Here, we performed a phylogenetic analysis of the photosystem I subunits encoded in the FaRLiP gene cluster and analyzed the available structural data to predict ancestral characteristics of FRL-absorbing photosystem I. The analysis suggests that FRL-specific photosystem I subunits arose relatively late during the evolution of cyanobacteria when compared with some of the FRL-specific subunits of photosystem II, and that the order Nodosilineales, which include strains like and sp. PCC 7335, could have obtained FaRLiP via horizontal gene transfer. We show that the ancestral form of FRL-absorbing photosystem I contained three chlorophyll -binding sites in the PsaB2 subunit, and a rotated chlorophyll molecule in the A site of the electron transfer chain. Along with our previous study of photosystem II expressed during FaRLiP, these studies describe the molecular evolution of the photosystem complexes encoded by the FaRLiP gene cluster.
PubMed: 38053766
DOI: 10.3389/fpls.2023.1289199 -
Biochimica Et Biophysica Acta.... Jun 2021Oxygenic photosynthesis starts with the oxidation of water to O, a light-driven reaction catalysed by photosystem II. Cyanobacteria are the only prokaryotes capable of...
Oxygenic photosynthesis starts with the oxidation of water to O, a light-driven reaction catalysed by photosystem II. Cyanobacteria are the only prokaryotes capable of water oxidation and therefore, it is assumed that the origin of oxygenic photosynthesis is a late innovation relative to the origin of life and bioenergetics. However, when exactly water oxidation originated remains an unanswered question. Here we use phylogenetic analysis to study a gene duplication event that is unique to photosystem II: the duplication that led to the evolution of the core antenna subunits CP43 and CP47. We compare the changes in the rates of evolution of this duplication with those of some of the oldest well-described events in the history of life: namely, the duplication leading to the Alpha and Beta subunits of the catalytic head of ATP synthase, and the divergence of archaeal and bacterial RNA polymerases and ribosomes. We also compare it with more recent events such as the duplication of Cyanobacteria-specific FtsH metalloprotease subunits and the radiation leading to Margulisbacteria, Sericytochromatia, Vampirovibrionia, and other clades containing anoxygenic phototrophs. We demonstrate that the ancestral core duplication of photosystem II exhibits patterns in the rates of protein evolution through geological time that are nearly identical to those of the ATP synthase, RNA polymerase, or the ribosome. Furthermore, we use ancestral sequence reconstruction in combination with comparative structural biology of photosystem subunits, to provide additional evidence supporting the premise that water oxidation had originated before the ancestral core duplications. Our work suggests that photosynthetic water oxidation originated closer to the origin of life and bioenergetics than can be documented based on phylogenetic or phylogenomic species trees alone.
Topics: Bacterial Proteins; Cyanobacteria; Evolution, Molecular; Oxidation-Reduction; Oxygen; Photosynthesis; Photosystem II Protein Complex; Phylogeny
PubMed: 33617856
DOI: 10.1016/j.bbabio.2021.148400 -
The FEBS Journal Jun 2020In photosynthesis, light energy is captured by pigments bound to light-harvesting antenna proteins (LHC) that then transfer the energy to the photosystem (PS) cores to... (Review)
Review
In photosynthesis, light energy is captured by pigments bound to light-harvesting antenna proteins (LHC) that then transfer the energy to the photosystem (PS) cores to initiate photochemical reactions. The LHC proteins surround the PS cores to form PS-LHC supercomplexes. In order to adapt to a wide range of light environments, photosynthetic organisms have developed a large variety of pigments and antenna proteins to utilize the light energy efficiently under different environments. Diatoms are a group of important eukaryotic algae and possess fucoxanthin (Fx) chlorophyll a/c proteins (FCP) as antenna which have exceptional capabilities of harvesting blue-green light under water and dissipate excess energy under strong light conditions. We have solved the structure of a PSII-FCPII supercomplex from a centric diatom Chaetoceros gracilis by cryo-electron microscopy, and also the structure of an isolated FCP dimer from a pennate diatom Phaeodactylum tricornutum by X-ray crystallography at a high resolution. These results revealed the oligomerization states of FCPs distinctly different from those of LHCII found in the green lineage organisms, the detailed binding patterns of Chl c and Fxs, a huge pigment network, and extensive protein-protein, pigment-protein, and pigment-pigment interactions within the PSII-FCPII supercomplex. These results therefore provide a solid structural basis for examining the detailed mechanisms of the highly efficient energy transfer and quenching processes in diatoms.
Topics: Chlorophyll A; Cryoelectron Microscopy; Diatoms; Energy Transfer; Light-Harvesting Protein Complexes; Photosynthesis; Photosystem II Protein Complex; Xanthophylls
PubMed: 31854056
DOI: 10.1111/febs.15183