The identification of the Photosystem II reaction center: a personal story

Satoh, Kimiyuki

doi:10.1007/1-4020-3324-9_25

Cited by 5 publications

(5 citation statements)

References 52 publications

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“…In accordance with this proposal, it has been demonstrated that incubation of PSII membranes with glucose-glucose oxidase in the aerobic conditions induces a significant oxidation of the non-heme iron, probably due to formation of H 2 O 2 ( , ). Furthermore, H 2 O 2 treatment of PSII core complexes, which contain the non-heme iron, was shown to cause more pronounced damage to the proteins than when isolated PSII reaction centers, which lack the non-heme iron, are treated with H 2 O 2 ( , ). Because of the observation that a residual level of H 2 O 2 disproportion was observed in catalase-free PSII membranes, it was suggested that the non-heme iron might reduce H 2 O 2 via Fenton chemistry ().…”

Section: Discussionmentioning

confidence: 99%

Hydroxyl Radical Generation by Photosystem II

et al. 2004

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The photogeneration of hydroxyl radicals (OH(*)) in photosystem II (PSII) membranes was studied using EPR spin-trapping spectroscopy. Two kinetically distinguishable phases in the formation of the spin trap-hydroxyl (POBN-OH) adduct EPR signal were observed: the first phase (t(1/2) = 7.5 min) and the second phase (t(1/2) = 30 min). The generation of OH(*) was found to be suppressed in the absence of the Mn-complex, but it was restored after readdition of an artificial electron donor (DPC). Hydroxyl radical generation was also lost in the absence of oxygen, whereas it was stimulated when the oxygen concentration was increased. The production of OH(*) during the first kinetic phase was sensitive to the presence of SOD, whereas catalase and EDTA diminished the production of OH(*) during the second kinetic phase. The POBN-OH adduct EPR signal during the first phase exhibits a similar pH-dependence as the ability to oxidize the non-heme iron, as monitored by the Fe(3+) (g = 8) EPR signal: both EPR signals gradually decreased as the pH value was lowered below pH 6.5 and were absent at pH 5. Sodium formate decreases the production of OH(*) in intact and Mn-deleted PSII membranes. Upon illumination of PSII membranes, both superoxide, as measured by EPR signal from the spin trap-superoxide (EMPO-OOH) adduct, and H(2)O(2), measured colormetrically, were generated. These results indicated that OH(*) is produced on the electron acceptor side of PSII by two different routes, (1) O(2)(*)(-), which is generated by oxygen reduction on the acceptor side of PSII, interacts with a PSII metal center, probably the non-heme iron, to form an iron-peroxide species that is further reduced to OH(*) by an electron from PSII, presumably via Q(A)(-), and (2) O(2)(*)(-) dismutates to form free H(2)O(2) that is then reduced to OH(*) via the Fenton reaction in the presence of metal ions, the most likely being Mn(2+) and Fe(2+) released from photodamaged PSII. The two different routes of OH(*) generation are discussed in the context of photoinhibition.

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Section: Discussionmentioning

confidence: 99%

Hydroxyl Radical Generation by Photosystem II

et al. 2004

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“…The protein was first named as ''Peak D'' by Ellis in his pulselabeling experiments, but later re-named as ''D1 protein'' and also as ''herbicide-or Q B -binding protein'' (for reviews, see Satoh 2003;Nixon et al 2005;Edelman and Mattoo 2006). This protein was finally established as a component of the PS II reaction center (Nanba and Satoh 1987;Satoh et al 1987;Marder et al 1987).…”

Section: History Of Discoverymentioning

confidence: 98%

The carboxyl-terminal processing of precursor D1 protein of the photosystem II reaction center

Satoh

Yamamoto

2007

Photosynth Res

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The D1 protein, a key subunit of photosystem II reaction center, is synthesized as a precursor form with a carboxyl-terminal extension, in oxygenic photosynthetic organisms with some exceptions. This part of the protein is removed by the action of an endopeptidase, and the proteolytic processing is indispensable for the manifestation of oxygen-evolving activity in photosynthesis. The carboxyl-terminus of mature D1 protein, which appears upon the cleavage, has recently been demonstrated to be a ligand for a manganese atom in the Mn(4)Ca-cluster, which is responsible for the water oxidation chemistry in photosystem II, based on the isotope-edited Fourier transform infrared spectroscopy and the X-ray crystallography. On the other hand, the structure of a peptidase involved in the cleavage of precursor D1 protein has been resolved at a higher resolution, and the enzyme-substrate interactions have extensively been analyzed both in vivo and in vitro. The present article briefly summarizes the history of research and the present state of our knowledge on the carboxyl-terminal processing of precursor D1 protein in the photosystem II reaction center.

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“…The BBY preparation has had enormous implications both for biochemical and biophysical measurements. It provided, for example, the starting point for isolating the PS II RC consisting of the D1 and D2 proteins and the αand β-subunits of cytochrome b559 by Nanba and Satoh (1987); see also Satoh (2003). My colleagues and I were able to reproduce their method (Barber et al 1987;Marder et al 1987) and later modified it so as to increase the stability of the isolated complex (Chapman et al 1988).…”

Section: The Era Of Ps II Biochemistrymentioning

confidence: 99%

Engine of Life and Big Bang of Evolution: A Personal Perspective

Barber

2004

Photosynthesis Research

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Photosystem II (PS II) is the engine for essentially all life on our planet and its beginning 2.5 billion years ago was the 'big bang of evolution.' It produces reducing equivalents for making organic compounds on an enormous scale and at the same time provides us with an oxygenic atmosphere and protection against UV radiation (in the form of the ozone layer). In 1967, when I began my career in photosynthesis research, little was known about PS II. The Z-scheme had been formulated [Hill and Bendall (1960) Nature 186: 136-137] and Boardman and Anderson [(1964) Nature 203: 166-167] had isolated PS II as a discrete biochemical entity. PS II was known not only to be the source of oxygen but of variable chlorophyll fluorescence [Duysens and Sweers (1963) In: Studies on Microalgae and Photosynthetic Bacteria, pp. 353-372. University of Tokyo Press, Tokyo] and delayed chlorophyll fluorescence [Arnold and Davidson (1954) J Gen Physiol 37: 677-684]. P680 had just been discovered [Döring et al. (1967) Z Naturforsch 22b: 639-644]. No wonder the 'black box of PS II' was described at that time by Bessel Kok and George Cheniae [Current Topics in Bioenergetics 1: 1-47 (1966)] as the 'inner sanctum of photosynthesis.' What a change in our level of understanding of PS II since then! The contributions of many talented scientists have unraveled the mechanisms and structural basis of PS II function and we are now very close to revealing the molecular details of the remarkable and thermodynamically demanding reaction which it catalyzes, namely the splitting of water into its elemental constituents. It has been a privilege to be involved in this journey.

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The identification of the Photosystem II reaction center: a personal story

Abstract: This minireview is about the path that led me to the identification of the Photosystem II reaction center in oxygenic photosynthesis. It is based mostly on my own experiences and viewpoints.

Cited by 5 publications

References 52 publications

Hydroxyl Radical Generation by Photosystem II

Hydroxyl Radical Generation by Photosystem II

The carboxyl-terminal processing of precursor D1 protein of the photosystem II reaction center

Engine of Life and Big Bang of Evolution: A Personal Perspective

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