Photosystem II oxygen-evolving

Ishida N, Sugiura M, Rappaport F, Lai TL, Rutherford AW, Boussac A. Biosynthetic exchange of bromide for chloride and strontium for calcium in the photosystem II oxygen-evolving enzymes. J Biol Chem. 2008 283(19) 13330-40. 

A Boussac and AW Rutherford (1988) S-state formation after Ca depletion in the photosystem II oxygen-evolving complex. Chem Scripta 28A 123-126... 

In the realm of biology, a step in the chain of charge transfers in the photosystem II oxygen-evolving complex (PSII/OEC) may provide an example of pcet according to the following scheme (15). For a consecutive pathway, et followed by pt, the steps are... 

The pulsed EPR technique of Electron Spin Echo Envelope Modulation (ESEEM) is used to measure the nuclear transition frequencies of paramagnetic nuclei magnetically coupled to unpaired electron spins. We have employed this technique to study the Mn center of the Photosystem II oxygen-evolving complex. ESEEM measurements were performed on the multiline Mn EPR signal associated with the S2 state of the Kok cycle. 

Before discussing data on intact systems I shall flrst present some results from isolated photosystem (PS) I and PS II particles. It will become clear from the discussion that the energy transfer processes in the photosystems of oxygen-evolving photosynthesis are intimately related with the primary charge separation processes in the reaction centers. 

Ghanotakis, D. F, and Yocum, C. F, 1990. Photosystem II and die oxygen-evolving complex. Annual Review of Plant Physiology and Plant Molecular 41 255-276. 

Manganese is the third most abundant transition element [1]. It is present in a number of industrial, hiological, and environmental systems, representative examples of which include manganese oxide batteries [2] the oxygen-evolving center of photosystem II (PSII) [3] manganese catalase, peroxidase, superoxide dismutase (SOD), and other enzymes [4, 5] chiral epoxidation catalysts [6] and deep ocean nodules [7]. Oxidation-reduction chemistry plays a central role in the function of most, if not all, of these examples. 

Scheme 5 The S-state cycle of the oxygen-evolving center in photosystem II [114]. 

Kainiya, N. Shen, J.-R. (2003) Crystal structure of oxygen-evolving photosystem II from Thermosynechococcus vulcanus at 3.7 A resolution. Proc. Natl. Acad. Sci. USA 100, 98-103. 

Rutherford, A. W., Photosystem II, the water-splitting enzyme. Trends Biochem. Sci. 14 227, 1989. A readable account of current results and speculations on the oxygen-evolving complex. 

Triazines inhibit photosynthesis in all organisms with oxygen-evolving photosystems. They block photosynthetic electron transport by displacing plastoquinone from a specific-binding site on the D1 protein subunit of photosystem II (PS II). This mode of action is shared with several structurally different groups of other herbicides. The elucidation of the mechanism of the inhibitory action is followed in this review. 

Rogner, M., Dekker, J.P., Boekema, E.J. and Witt, H.T. 1987. Size, shape and mass of the oxygen evolving photosystem II complex from the thermophilic cyanobacterium Synechococcus sp. FEBS Lett., 219,207-211. 

Cady C, Crabtree RH, Brudvig GW. Functional models for the oxygen-evolving complex of photosystem II. Coord Chem Rev 2008 252 444-55. 

Umena Y, Kawakami K, Shen JR, Kamiya N. Crystal structure of oxygen-evolving photosystem II at a resolution of 1.9A. Nature. 2011 473(7345) 55-60. 

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