scholarly journals Metabolic Capacity of the Antarctic Cyanobacterium Phormidium pseudopriestleyi That Sustains Oxygenic Photosynthesis in the Presence of Hydrogen Sulfide

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 426
Author(s):  
Jessica E. Lumian ◽  
Anne D. Jungblut ◽  
Megan L. Dillion ◽  
Ian Hawes ◽  
Peter T. Doran ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Microbial Mats ◽  
D1 Protein ◽  
Thick Layer ◽  
Quinone Reductase ◽  
Oxygenic Photosynthesis ◽  
Oxygen Evolving Complex ◽  
Filamentous Cyanobacterium ◽  
Anoxygenic Photosynthesis ◽  
Multiple Copies

Sulfide inhibits oxygenic photosynthesis by blocking electron transfer between H2O and the oxygen-evolving complex in the D1 protein of Photosystem II. The ability of cyanobacteria to counter this effect has implications for understanding the productivity of benthic microbial mats in sulfidic environments throughout Earth history. In Lake Fryxell, Antarctica, the benthic, filamentous cyanobacterium Phormidium pseudopriestleyi creates a 1–2 mm thick layer of 50 µmol L−1 O2 in otherwise sulfidic water, demonstrating that it sustains oxygenic photosynthesis in the presence of sulfide. A metagenome-assembled genome of P. pseudopriestleyi indicates a genetic capacity for oxygenic photosynthesis, including multiple copies of psbA (encoding the D1 protein of Photosystem II), and anoxygenic photosynthesis with a copy of sqr (encoding the sulfide quinone reductase protein that oxidizes sulfide). The genomic content of P. pseudopriestleyi is consistent with sulfide tolerance mechanisms including increasing psbA expression or directly oxidizing sulfide with sulfide quinone reductase. However, the ability of the organism to reduce Photosystem I via sulfide quinone reductase while Photosystem II is sulfide-inhibited, thereby performing anoxygenic photosynthesis in the presence of sulfide, has yet to be demonstrated.

scholarly journals Untangling the sequence of events during the S2→ S3transition in photosystem II and implications for the water oxidation mechanism

2020 ◽  
Vol 117 (23) ◽  
pp. 12624-12635 ◽  
Author(s):  
Mohamed Ibrahim ◽  
Thomas Fransson ◽  
Ruchira Chatterjee ◽  
Mun Hon Cheah ◽  
Rana Hussein ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Water Oxidation ◽  
Donor Site ◽  
Oxidation Mechanism ◽  
Oxygenic Photosynthesis ◽  
Acceptor Site ◽  
Oxygen Evolving Complex ◽  
Ps Ii ◽  
Sequence Of Events ◽  
Large Channel

In oxygenic photosynthesis, light-driven oxidation of water to molecular oxygen is carried out by the oxygen-evolving complex (OEC) in photosystem II (PS II). Recently, we reported the room-temperature structures of PS II in the four (semi)stable S-states, S1, S2, S3, and S0, showing that a water molecule is inserted during the S2→ S3transition, as a new bridging O(H)-ligand between Mn1 and Ca. To understand the sequence of events leading to the formation of this last stable intermediate state before O2formation, we recorded diffraction and Mn X-ray emission spectroscopy (XES) data at several time points during the S2→ S3transition. At the electron acceptor site, changes due to the two-electron redox chemistry at the quinones, QAand QB, are observed. At the donor site, tyrosine YZand His190 H-bonded to it move by 50 µs after the second flash, and Glu189 moves away from Ca. This is followed by Mn1 and Mn4 moving apart, and the insertion of OX(H) at the open coordination site of Mn1. This water, possibly a ligand of Ca, could be supplied via a “water wheel”-like arrangement of five waters next to the OEC that is connected by a large channel to the bulk solvent. XES spectra show that Mn oxidation (τ of ∼350 µs) during the S2→ S3transition mirrors the appearance of OXelectron density. This indicates that the oxidation state change and the insertion of water as a bridging atom between Mn1 and Ca are highly correlated.

scholarly journals Variation in Sulfide Tolerance of Photosystem II in Phylogenetically Diverse Cyanobacteria from Sulfidic Habitats

2004 ◽  
Vol 70 (2) ◽  
pp. 736-744 ◽  
Author(s):  
Scott R. Miller ◽  
Brad M. Bebout
Keyword(s):  
Photosystem Ii ◽  
Fluorescence Induction ◽  
Oxygenic Photosynthesis ◽  
Chlorophyll Fluorescence Induction ◽  
Oxygen Evolving Complex ◽  
Sulfide Toxicity ◽  
Molecular Phylogenetic ◽  
Dynamic Trait ◽  
Oxygen Evolving ◽  
Sulfide Tolerance

ABSTRACT Physiological and molecular phylogenetic approaches were used to investigate variation among 12 cyanobacterial strains in their tolerance of sulfide, an inhibitor of oxygenic photosynthesis. Cyanobacteria from sulfidic habitats were found to be phylogenetically diverse and exhibited an approximately 50-fold variation in photosystem II performance in the presence of sulfide. Whereas the degree of tolerance was positively correlated with sulfide levels in the environment, a strain's phenotype could not be predicted from the tolerance of its closest relatives. These observations suggest that sulfide tolerance is a dynamic trait primarily shaped by environmental variation. Despite differences in absolute tolerance, similarities among strains in the effects of sulfide on chlorophyll fluorescence induction indicated a common mode of toxicity. Based on similarities with treatments known to disrupt the oxygen-evolving complex, it was concluded that sulfide toxicity resulted from inhibition of the donor side of photosystem II.

Evolution of Oxygenic Photosynthesis

2017 ◽  
Author(s):  
Donald Eugene Canfield
Keyword(s):  
Photosystem Ii ◽  
Photosystem I ◽  
Evolutionary History ◽  
Oxygenic Photosynthesis ◽  
Oxygen Evolving Complex ◽  
History Of ◽  
Oxygen Evolving ◽  
Evolution Of Oxygen ◽  
Basic Constituent ◽  
Key Questions

This chapter discusses the evolution of oxygen-producing organisms by considering the evolution and assembly of its basic constituent parts. It focuses on the following key questions: (1) What is the evolutionary history of chlorophyll? (2) What are the evolutionary histories of photosystem I and photosystem II (PSII)? (3) What is the origin of the oxygen-evolving complex in PSII? And finally, (4) what is the evolutionary history of Rubisco? In addressing these, the chapter seeks to understand the complex path leading to the evolution of oxygenic photosynthesis on Earth. This event was one of the major transforming events in the history of life. With no oxygenic photosynthesis, there would be no oxygen in the atmosphere; there would also be no plants, no animals, and nobody to tell this story.

scholarly journals Photosystem II oxygen-evolving complex photoassembly displays an inverse H/D solvent isotope effect under chloride-limiting conditions

2019 ◽  
Vol 116 (38) ◽  
pp. 18917-18922 ◽  
Author(s):  
David J. Vinyard ◽  
Syed Lal Badshah ◽  
M. Rita Riggio ◽  
Divya Kaur ◽  
Annaliesa R. Fanguy ◽  
...  
Keyword(s):  
Amino Acid ◽  
Photosystem Ii ◽  
Isotope Effect ◽  
Water Oxidation ◽  
Oxygenic Photosynthesis ◽  
Oxygen Evolving Complex ◽  
Solvent Isotope Effect ◽  
Solvent Isotope ◽  
Oxygen Evolving ◽  
Protein Environment

Photosystem II (PSII) performs the solar-driven oxidation of water used to fuel oxygenic photosynthesis. The active site of water oxidation is the oxygen-evolving complex (OEC), a Mn4CaO5 cluster. PSII requires degradation of key subunits and reassembly of the OEC as frequently as every 20 to 40 min. The metals for the OEC are assembled within the PSII protein environment via a series of binding events and photochemically induced oxidation events, but the full mechanism is unknown. A role of proton release in this mechanism is suggested here by the observation that the yield of in vitro OEC photoassembly is higher in deuterated water, D2O, compared with H2O when chloride is limiting. In kinetic studies, OEC photoassembly shows a significant lag phase in H2O at limiting chloride concentrations with an apparent H/D solvent isotope effect of 0.14 ± 0.05. The growth phase of OEC photoassembly shows an H/D solvent isotope effect of 1.5 ± 0.2. We analyzed the protonation states of the OEC protein environment using classical Multiconformer Continuum Electrostatics. Combining experiments and simulations leads to a model in which protons are lost from amino acid that will serve as OEC ligands as metals are bound. Chloride and D2O increase the proton affinities of key amino acid residues. These residues tune the binding affinity of Mn2+/3+ and facilitate the deprotonation of water to form a proposed μ-hydroxo bridged Mn2+Mn3+ intermediate.

scholarly journals Psb35 Protein Stabilizes the CP47 Assembly Module and Associated High-Light Inducible Proteins during the Biogenesis of Photosystem II in the Cyanobacterium Synechocystis sp. PCC6803

2020 ◽  
Author(s):  
Guillem Pascual-Aznar ◽  
Grzegorz Konert ◽  
Martina Bečková ◽  
Eva Kotabová ◽  
Zdenko Gardian ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
High Light ◽  
Oxygenic Photosynthesis ◽  
Oxygen Evolving Complex ◽  
Primary Charge Separation ◽  
Light Regimes ◽  
Pulldown Assay ◽  
Antenna Module ◽  
Oxygen Evolving ◽  
Synechocystis Sp

Abstract Photosystem II (PSII) is a large membrane protein complex performing primary charge separation in oxygenic photosynthesis. The biogenesis of PSII is a complicated process that involves a coordinated linking of assembly modules in a precise order. Each such module consists of one large chlorophyll (Chl)-binding protein, number of small membrane polypeptides, pigments and other cofactors. We isolated the CP47 antenna module from the cyanobacterium Synechocystis sp. PCC 6803 and found that it contains a 11-kDa protein encoded by the ssl2148 gene. This protein was named Psb35 and its presence in the CP47 module was confirmed by the isolation of FLAG-tagged version of Psb35. Using this pulldown assay, we showed that the Psb35 remains attached to CP47 after the integration of CP47 into PSII complexes. However, the isolated Psb35-PSIIs were enriched with auxiliary PSII assembly factors like Psb27, Psb28-1, Psb28-2 and RubA while they lacked the lumenal proteins stabilizing the PSII oxygen-evolving complex. In addition, the Psb35 co-purified with a large unique complex of CP47 and photosystem I trimer. The absence of Psb35 led to a lower accumulation and decreased stability of the CP47 antenna module and associated high-light-inducible proteins but did not change the growth rate of the cyanobacterium under the variety of light regimes. Nevertheless, in comparison with WT, the Psb35-less mutant showed an accelerated pigment bleaching during prolonged dark incubation. The results suggest an involvement of Psb35 in the life cycle of cyanobacterial Chl-binding proteins, especially CP47.

scholarly journals Photosystem II assembly factor HCF136 from A. thaliana at 1.67 Å resolution

2014 ◽  
Vol 70 (a1) ◽  
pp. C1170-C1170
Author(s):  
Roland Bergdahl ◽  
Christin Grundström ◽  
Patrik Storm ◽  
Wolfgang Schröder ◽  
Uwe Sauer
Keyword(s):  
Photosystem Ii ◽  
Water Splitting ◽  
D1 Protein ◽  
Oxygenic Photosynthesis ◽  
Reaction Centre ◽  
Cytochrome B559 ◽  
Irreversible Damage ◽  
Redox Active ◽  
Assembly Factor ◽  
High Level

The High Chlorophyll Fluorescence 136 protein (HCF136) is essential for the assembly and repair of Photosystem II (PSII) and its central reaction centre (RC)[1]. HCF136 is an abundant protein in the thylakoid lumen and has been suggested to directly interact with subunits of the RC. The multi-subunit pigment-protein PSII complex is imbedded in the thylakoid membrane of the oxygenic photosynthetic organisms, and responsible for water splitting during oxygenic photosynthesis. PSII harbours more than 20 different integral and peripheral membrane proteins and its assembly requires a high level of coordination[2]. Two proteins D1 (psbA) and D2 (psbD) form the core of the complex and bind most of the redox-active co-factors. The PSII RC contains, in addition to D1 and D2, the intrinsic PsbI subunit and cytochrome b559. Light is a harmful substrate and subunits are damaged during the water-splitting reaction. The largest irreversible damage is experienced by the central D1 protein that has the highest turnover rate of all thylakoid proteins. Analysis of mutated A. thaliana has identified HCF136 as an essential factor for PSII RC assembly and RC turnover and repair[3]. In order to gain functional and structural insight in the way the HCF136 protein is involved in the PSII repair cycle, we have cloned, expressed, purified and crystallized the HCF136 protein from A. thaliana. Here we present the structure of this doughnut shaped WD40 domain family protein determined at 1.67 Å resolution. Biochemical and biophysical analysis of HCF136 and components of the PSII RC are under way.

scholarly journals Synthesis and assembly of thylakoid protein complexes: multiple assembly steps of photosystem II

2005 ◽  
Vol 388 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Anne ROKKA ◽  
Marjaana SUORSA ◽  
Ammar SALEEM ◽  
Natalia BATTCHIKOVA ◽  
Eva-Mari ARO
Keyword(s):  
Photosystem Ii ◽  
Molecular Mass ◽  
Spinacia Oleracea ◽  
Protein Complexes ◽  
D1 Protein ◽  
Oxygen Evolving Complex ◽  
Reaction Centre ◽  
Light Intensities ◽  
Thylakoid Protein

To study the synthesis and assembly of multisubunit thylakoid protein complexes, we performed [35S]Met pulse and chase experiments with isolated chloroplasts and intact leaves of spinach (Spinacia oleracea L.), followed by Blue Native gel separation of the (sub)complexes and subsequent identification of the newly synthesized and assembled protein subunits. PSII (photosystem II) core subunits were the most intensively synthesized proteins, particularly in vitro and at high light intensities in vivo, and could be sequestered in several distinct PSII subassemblies. Newly synthesized D1 was first found in the reaction centre complex that also contained labelled D2 and two labelled low-molecular-mass proteins. The next biggest PSII subassembly contained CP47 also. Then PsbH was assembled together with at least two other labelled chloroplast-encoded low-molecular-mass subunits, PsbM and PsbTc, and a nuclear-encoded PsbR. Subsequently, CP43 was inserted into the PSII complex concomitantly with PsbK. These assembly steps seemed to be essential for the dimerization of PSII core monomers. Intact PSII core monomer was the smallest subcomplex harbouring the newly synthesized 33 kDa oxygen-evolving complex protein PsbO. Nuclear-encoded PsbW was synthesized only at low light intensities concomitantly with Lhcb polypeptides and was distinctively present in PSII–LHCII (where LHC stands for light-harvesting complex) supercomplexes. The PsbH protein, on the contrary, was vigorously synthesized and incorporated into PSII core monomers together with the D1 protein, suggesting an intrinsic role for PsbH in the photoinhibition-repair cycle of PSII.

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