Alternating electron and proton transfer steps in photosynthetic water oxidation
نویسندگان
چکیده
منابع مشابه
Alternating electron and proton transfer steps in photosynthetic water oxidation.
Water oxidation by cyanobacteria, algae, and plants is pivotal in oxygenic photosynthesis, the process that powers life on Earth, and is the paradigm for engineering solar fuel-production systems. Each complete reaction cycle of photosynthetic water oxidation requires the removal of four electrons and four protons from the catalytic site, a manganese-calcium complex and its protein environment ...
متن کاملElectrostatics and proton transfer in photosynthetic water oxidation.
Photosystem II (PSII) oxidizes two water molecules to yield dioxygen plus four protons. Dioxygen is released during the last out of four sequential oxidation steps of the catalytic centre (S(0) --> S(1), S(1) --> S(2), S(2) --> S(3), S(3) --> S(4) --> S(0)). The release of the chemically produced protons is blurred by transient, highly variable and electrostatically triggered proton transfer at...
متن کاملCofactor X of photosynthetic water oxidation: electron transfer, proton release, and electrogenic behaviour in chloride-depleted Photosystem II
Ž . Ž . Four quanta of light, absorbed by Photosystem II PS II , drive the catalytic center of oxygen evolution OEC through w x Ž . Ž . five transitions which are named S ́S to S ́S TMS 1 . Manganese Mn , tyrosine Y and a chemically 0 1 3 4 0 4 Z ill-defined compound, X, serve as redox cofactors. Transient optical absorption spectra of PS II core particles have led us to ) ) y w x propose that ...
متن کاملProton and hydrogen currents in photosynthetic water oxidation.
The photosynthetic processes that lead to water oxidation involve an evolution in time from photon dynamics to photochemically-driven electron transfer to coupled electron/proton chemistry. The redox-active tyrosine, Y(Z), is the component at which the proton currents necessary for water oxidation are switched on. The thermodynamic and kinetic implications of this function for Y(Z) are discusse...
متن کاملCoupling of electron and proton transfer in the photosynthetic water oxidase.
According to current estimates, the photosynthetic water oxidase functions with a quite restricted driving force. This emphasizes the importance of the catalytic mechanisms in this enzyme. The general problem of coupling electron and proton transfer is discussed from this viewpoint and it is argued that 'weak coupling' is preferable to 'strong coupling'. Weak coupling can be achieved by facilit...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 2012
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.1206266109