P680: Difference between revisions
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P680 is the strongest biological oxidizing agent known. It has an estimated redox potential of ~1.3 V<ref>Rappaport F, Guergova-Kuras M, Nixon PJ, Diner BA and Lavergne J (2002): Kinetics and pathways of charge recombination in photosystem II. Biochemistry 41, 8518-8527.</ref>. This makes it possible to oxidize [[water]] during [[Photosynthesis|oxygenic photosynthesis]]. |
P680 is the strongest biological oxidizing agent known. It has an estimated redox potential of ~1.3 V<ref>Rappaport F, Guergova-Kuras M, Nixon PJ, Diner BA and Lavergne J (2002): Kinetics and pathways of charge recombination in photosystem II. Biochemistry 41, 8518-8527.</ref>. This makes it possible to oxidize [[water]] during [[Photosynthesis|oxygenic photosynthesis]]. |
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==Notes== |
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==See also== |
==See also== |
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*[[P700]]. |
*[[P700]]. |
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Revision as of 12:39, 19 September 2008
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P680, or Photosystem II primary donor, (where P stands for pigment) is a group of pigments associated with photosystem II and consists of 4 chlorophyll a molecules[1]. These four molecules are excitonically coupled which means that they effectively act as a single entity, i.e. they are excited as if they were a single molecule. The 680 number is its absorption maximum in the red part of the visible spectrum (680 nm). The primary donor receives excitation energy either by absorbing a photon of suitable frequency (colour) or by excitation energy transfer from other chlorophylls within photosystem II. During excitation an electron is excited to a higher energy level. This electron is subsequently captured by the primary electron acceptor, a pheophytin molecule located within photosystem II near P680. The oxidized P680 (P680+) is subsequently reduced by an electron originating from water (via Oxygen evolving complex).
P680 is the strongest biological oxidizing agent known. It has an estimated redox potential of ~1.3 V[2]. This makes it possible to oxidize water during oxygenic photosynthesis.
Notes
- ^ Raszewski G, Diner BA, Schlodder E and Renger T (2008) Spectroscopic properties of reaction center pigments in photosystem II core complexes: Revision of the multimer model. Biophys. J. 95:105-119
- ^ Rappaport F, Guergova-Kuras M, Nixon PJ, Diner BA and Lavergne J (2002): Kinetics and pathways of charge recombination in photosystem II. Biochemistry 41, 8518-8527.
See also
- P700.
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