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Photosystem II, DII subunit (also called Q(A)) This model describes the Photosystem II, DII subunit (also called Q(A)) in bacterial and its equivalents in chloroplast of algae and higher plants. Photosystem II is in many ways functionally equivalent to bacterial reaction center. At the core of Photosystem II are several light harvesting cofactors including plastoquinones, pheophytins, phyloquinones etc. These cofactors are intimately associated with the polypeptides, which principally including subunits DI, DII, Cyt.b, Cyt.f and iron-sulphur protein. Together they participate in the electron transfer reactions that lead to the net production of the reducting equivalents in the form of NADPH, which are used for reduction of CO2 to carbohydrates(C6H1206). Phosystem II operates during oxygenic photosynthesis and principal electron donor is H2O. Although no high resolution X-ray structural data is presently available, recently a 3D structure of the supercomplex has been described by cryo-electron microscopy. Besides a huge body of literature exits that describes function using a variety of biochemical and biophysical techniques. [Energy metabolism, Electron transport, Energy metabolism, Photosynthesis] |
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