Bicarbonate is an essential constituent of the water-oxidizing complex of photosystem II

Allakhverdiev, Suleyman I.; Yruela, Inmaculada; Picorel, Rafael; Klimov, Vyacheslav V.

doi:10.1073/pnas.94.10.5050

Cited by 81 publications

(66 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A larger ΔE m (∼50 mV) in higher plants than in cyanobacteria is consistent with the report by Krieger and Rutherford (15). particles in the presence of free Mn 2+ and Ca 2+ and that the addition of bicarbonate (1-5 mM) causes a considerable increase in both the rate and the yield of the photo-assembled oxygen-evolving complex (17,(19)(20)(21), even though bicarbonate was not found in the complex of recent crystallographic analysis. The stimulatory effect of bicarbonate in the photo-assembly of the oxygen-evolving complex is evidently based on the formation of easily oxidizable Mn-bicarbonate complexes (22), its participation in proton exchange within the oxygen-evolving complex (17,(21)(22)(23), and its suppression of photodamage to PS II (17,23,24).…”

Section: Resultssupporting

confidence: 79%

See 1 more Smart Citation

Redox potentials of primary electron acceptor quinone molecule (Q _A ) ⁻ and conserved energetics of photosystem II in cyanobacteria with chlorophyll a and chlorophyll d

Allakhverdiev

Watabe

Kojima

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

In a previous study, we measured the redox potential of the primary electron acceptor pheophytin (Phe) a of photosystem (PS) II in the chlorophyll d-dominated cyanobacterium Acaryochloris marina and a chlorophyll a-containing cyanobacterium, Synechocystis. We obtained the midpoint redox potential (E m ) values of −478 mV for A. marina and −536 mV for Synechocystis. In this study, we measured the redox potentials of the primary electron acceptor quinone molecule (Q A ), i. ) of A. marina was determined to be +64 mV without the Mn cluster and was estimated to be −66 to −86 mV with a Mn-depletion shift (130-150 mV), as observed with other organisms. The E m (Phe a/Phe a − ) in Synechocystis was measured to be −525 mV with the Mn cluster, which is consistent with our previous report. The Mn-depleted downshift of the potential was measured to be approximately −77 mV in Synechocystis, and this value was applied to A. marina (−478 mV); the E m (Phe a/Phe a − ) was estimated to be approximately −401 mV. These values gave rise to a ΔG PhQ of −325 mV for A. marina and −383 mV for Synechocystis. In the two cyanobacteria, the energetics in PS II were conserved, even though the potentials of Q A − and Phe a − were relatively shifted depending on the special pair, indicating a common strategy for electron transfer in oxygenic photosynthetic organisms.photosynthesis | photochemical reaction C hlorophylls (Chls) are key pigments for photosynthesis, and oxygenic photosynthetic organisms containing Chls are found all over the world-they sustain all terrestrial life through the primary production of organic molecules and the production of oxygen. Chl a and its derivatives, pheophytin (Phe) a and Chl a epimer (Chl a′), are used as the electron transfer components in photosystem (PS) II and PS I, respectively, except for in two taxonomic groups, marine cyanobacteria Prochlorococcus spp. containing divinyl-Chl a (1) and marine cyanobacteria Acaryochloris spp. containing Chl d (2). Consequently, experimental and theoretical analyses of the electron transfer system in oxygenic photosynthesis have been exclusively performed in Chl a-containing organisms, and the basic concept of the photosynthetic electron flow has been constructed on the basis of Chl a. However, our understanding of photosynthetic electron transfer is not yet complete because the reaction systems with divinyl-Chl a and Chl d have not been fully analyzed as yet.Since the discovery of Chl d in Acaryochloris marina in 1996 (3, 4), questions have arisen on the whether the electron transfer system in this organism is significantly different from those with Chl a. Interestingly, the functional "special pair" are Chl d molecules in the reaction centers of PS I and II in A. marina (5, 6); however, in PS II, Phe a is the primary electron acceptor. Chl d gains light energy at longer wavelengths and with a lowered redox potential, by ∼80 mV, compared with that of Chl a in Synechocystis sp. PCC 6803 (hereafter referred to as Synechocystis) and spinach (7-11). However, the overall ...

show abstract

Section: Resultssupporting

confidence: 79%

“…Preparation of biochemically treated samples: Mn depletion. To obtain Mndepleted samples, Tris, CHES, and NH 2 OH treatments were performed on PS II complexes isolated from Synechocystis (17)(18)(19)(35)(36)(37). Reconstitution of Mn-depleted PS II complexes.…”

Section: Methodsmentioning

confidence: 99%

Redox potentials of primary electron acceptor quinone molecule (Q _A ) ⁻ and conserved energetics of photosystem II in cyanobacteria with chlorophyll a and chlorophyll d

Allakhverdiev

Watabe

Kojima

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Swader & Jacobson (1972) reported that high concentrations of AZ inhibited electron transport in thylakoids. Several more recent publications have indicated an involvement of HCO 3 -in donor side reactions of PSII (Klimov et al 1995;Allakhverdiev et al 1997). There are further indications that this thylakoid CA may be regulated in some unknown way by light and redox levels (Moubarak-Milad & Stemler 1994;Moskvin, Ovchinnikova & Ivanov 1996).…”

Section: Thylakoid Camentioning

confidence: 99%

Carbonic anhydrases in plants and algae

Moroney¹,

Bartlett²,

Samuelsson³

2001

Plant Cell Environ

108

View full text Add to dashboard Cite

Carbonic anhydrases catalyse the reversible hydration of CO 2 , increasing the interconversion between CO 2 and HCO 3 -+ H + in living organisms. The three evolutionarily unrelated families of carbonic anhydrases are designated a-, b-and g-CA. Animals have only the a-carbonic anhydrase type of carbonic anhydrase, but they contain multiple isoforms of this carbonic anhydrase. In contrast, higher plants, algae and cyanobacteria may contain members of all three CA families. Analysis of the Arabidopsis database reveals at least 14 genes potentially encoding carbonic anhydrases. The database also contains expressed sequence tags (ESTs) with homology to most of these genes. Clearly the number of carbonic anhydrases in plants is much greater than previously thought. Chlamydomonas, a unicellular green alga, is not far behind with five carbonic anhydrases already identified and another in the EST database. In algae, carbonic anhydrases have been found in the mitochondria, the chloroplast thylakoid, the cytoplasm and the periplasmic space. In C 3 dicots, only two carbonic anhydrases have been localized, one to the chloroplast stroma and one to the cytoplasm. A challenge for plant scientists is to identify the number, location and physiological roles of the carbonic anhydrases.

show abstract

“…More recently, Klimov's group and their collaborators followed up on these earlier works and found compelling evidence for involvement of bicarbonate in stimulating electron donation from Mn 2ϩ to apo-WOC-PSII, in which the inorganic core was first removed (24)(25)(26)(27). Importantly, they found that bicarbonate increases the binding affinity and photooxidation rate of the first two Mn II ions, implicating a high affinity pair of Mn II ions involved in bicarbonate-dependent electron transfer from Mn II (27).…”

Section: Was There a Transitional Electron Donor Before Water?mentioning

confidence: 99%

The origin of atmospheric oxygen on Earth: The innovation of oxygenic photosynthesis

Dismukes

Klimov

Baranov

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

325

240

View full text Add to dashboard Cite

The evolution of O2-producing cyanobacteria that use water as terminal reductant transformed Earth's atmosphere to one suitable for the evolution of aerobic metabolism and complex life. The innovation of water oxidation freed photosynthesis to invade new environments and visibly changed the face of the Earth. We offer a new hypothesis for how this process evolved, which identifies two critical roles for carbon dioxide in the Archean period. First, we present a thermodynamic analysis showing that bicarbonate (formed by dissolution of CO 2) is a more efficient alternative substrate than water for O 2 production by oxygenic phototrophs. This analysis clarifies the origin of the long debated ''bicarbonate effect'' on photosynthetic O 2 production. We propose that bicarbonate was the thermodynamically preferred reductant before water in the evolution of oxygenic photosynthesis. Second, we have examined the speciation of manganese(II) and bicarbonate in water, and find that they form Mnbicarbonate clusters as the major species under conditions that model the chemistry of the Archean sea. These clusters have been found to be highly efficient precursors for the assembly of the tetramanganese-oxide core of the water-oxidizing enzyme during biogenesis. We show that these clusters can be oxidized at electrochemical potentials that are accessible to anoxygenic phototrophs and thus the most likely building blocks for assembly of the first O 2 evolving photoreaction center, most likely originating from green nonsulfur bacteria before the evolution of cyanobacteria.bicarbonate ͉ carbon dioxide ͉ cyanobacteria ͉ evolution ͉ manganese O xygen (O 2 ) production by photosynthesis is by far the dominant global process that replenishes atmospheric and oceanic oxygen essential to sustain all aerobic life. Geochemical records of terrestrial oxides indicate that O 2 evolution must have taken place in the precursors to cyanobacteria before ca. 2.8 billion years ago and led to the accumulation of O 2 in the atmosphere (1, 2). The creation of a photosynthetic apparatus capable of splitting water into O 2 , protons, and electrons was the pivotal innovation in the evolution of life on Earth. For the first time photosynthesis had an unlimited source of electrons and protons by using water as reductant. By freeing photosynthesis from the availability of reduced chemical substances, the global production of organic carbon could be enormously increased and opened new environments for photosynthesis to occur. This event literally changed the face of the Earth. The accumulation of O 2 in the atmosphere led to the biological innovation of aerobic respiration, which harnesses a more powerful metabolic energy source. Because aerobic metabolism generates 18 times more energy (ATP) per metabolic input (hexose sugar) than does anaerobic metabolism, the engine of life became supercharged. This sequence of evolutionary steps enabled the emergence of complex, multicellular, energy-efficient, eukaryotic organisms.Comparisons of cyanobacteria, green algae, ...

show abstract

Bicarbonate is an essential constituent of the water-oxidizing complex of photosystem II

Cited by 81 publications

References 35 publications

Redox potentials of primary electron acceptor quinone molecule (Q _A ) ⁻ and conserved energetics of photosystem II in cyanobacteria with chlorophyll a and chlorophyll d

Redox potentials of primary electron acceptor quinone molecule (Q _A ) ⁻ and conserved energetics of photosystem II in cyanobacteria with chlorophyll a and chlorophyll d

Carbonic anhydrases in plants and algae

The origin of atmospheric oxygen on Earth: The innovation of oxygenic photosynthesis

Contact Info

Product

Resources

About

Bicarbonate is an essential constituent of the water-oxidizing complex of photosystem II

Cited by 81 publications

References 35 publications

Redox potentials of primary electron acceptor quinone molecule (Q A ) − and conserved energetics of photosystem II in cyanobacteria with chlorophyll a and chlorophyll d

Redox potentials of primary electron acceptor quinone molecule (Q A ) − and conserved energetics of photosystem II in cyanobacteria with chlorophyll a and chlorophyll d

Carbonic anhydrases in plants and algae

The origin of atmospheric oxygen on Earth: The innovation of oxygenic photosynthesis

Contact Info

Product

Resources

About

Redox potentials of primary electron acceptor quinone molecule (Q _A ) ⁻ and conserved energetics of photosystem II in cyanobacteria with chlorophyll a and chlorophyll d

Redox potentials of primary electron acceptor quinone molecule (Q _A ) ⁻ and conserved energetics of photosystem II in cyanobacteria with chlorophyll a and chlorophyll d