Manganese complexes oxygenation

In photosynthesis, water oxidation is accomplished by photosystem II (PSII), which is a large membrane-bound protein complex (158-161). To the central core proteins D1 and D2 are attached different cofactors, including a redox-active tyro-syl residue, tyrosine Z (Yz) (158-162), which is associated with a tetranuclear manganese complex (163). These components constitute the water oxidizing complex (WOC), the site in which the oxidation of water to molecular oxygen occurs (159, 160, 164). The organization is schematically shown in Fig. 18. 

OXII is responsible for the production of molecular oxygen in photosynthesis. A manganese complex, probably with four atoms of manganese, is attached to a protein molecule. It reduces OXjj which is recycled for use by another excited chlorophyll molecule in PS-II. In the redox reaction the manganese shuttles between two oxidation states with each manganese atom... 

Fig. 5 Vertical distribution of temperature (T), salinity (S), dissolved oxygen (O2), dissolved manganese (Mn diss), particulate manganese (Mn part), bivalent iron (Fe(II)), trivalent iron (Fe(III)), phosphate (P04), manganese complex (Mn com), organic phosphorus (Porg), and polyphosphate (Ppoly) at a station near Gelendzhik (St. 2618, September, 2006). Concentrations of chemical parameters are in xM. Distributions are plotted versus depth (m) at the top and versus density (og, kgm-3) at the bottom...

Beckmann K, Uchtenhagen H, Berggren G, et al. Formation of stoichiometrically lsO-labelled oxygen from the oxidation of lsO-enriched water mediated by a dinuclear manganese complex - a mass spectrometry and EPR study. Energy Environ Sci. 2008 1(6) 668-76. 

Dau H, Haumann M. Eight steps preceding 0-0 bond formation in oxygenic photosyn-thesis-A basic reaction cycle of the Photosystem II manganese complex. Biochim Biophys Acta Bioenerg. 2007 1767 472-83. 

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