Crystallographic and Computational Analysis of the Barrel Part of the PsbO Protein of Photosystem II: Carboxylate–Water Clusters as Putative Proton Transfer Relays and Structural Switches

Biochemistry ◽  
2016 ◽  
Vol 55 (33) ◽  
pp. 4626-4635 ◽  
Author(s):  
Martin Bommer ◽  
Ana-Nicoleta Bondar ◽  
Athina Zouni ◽  
Holger Dobbek ◽  
Holger Dau
2020 ◽  
Vol 22 (28) ◽  
pp. 15831-15841
Author(s):  
Naoki Sakashita ◽  
Hiroshi Ishikita ◽  
Keisuke Saito

In the channel of photosystem II, rigidly hydrogen-bonded water molecules facilitate the Grotthuss-like proton transfer, whereas flexible water molecules prevent proton transfer in the channel of aquaporin.


2019 ◽  
Vol 1860 (8) ◽  
pp. 611-617 ◽  
Author(s):  
Gourab Banerjee ◽  
Ipsita Ghosh ◽  
Christopher J. Kim ◽  
Richard J. Debus ◽  
Gary W. Brudvig

Biochemistry ◽  
1997 ◽  
Vol 36 (49) ◽  
pp. 15294-15302 ◽  
Author(s):  
Fabrice Rappaport ◽  
Jérôme Lavergne

2002 ◽  
Vol 357 (1426) ◽  
pp. 1383-1394 ◽  
Author(s):  
Cecilia Tommos

When photosynthetic organisms developed so that they could use water as an electron source to reduce carbon dioxide, the stage was set for efficient proliferation. Algae and plants spread globally and provided the foundation for our atmosphere and for O 2 –based chemistry in biological systems. Light–driven water oxidation is catalysed by photosystem II, the active site of which contains a redox–active tyrosine denoted Y Z , a tetramanganese cluster, calcium and chloride. In 1995, Gerald Babcock and co–workers presented the hypothesis that photosynthetic water oxidation occurs as a metallo–radical catalysed process. In this model, the oxidized tyrosine radical is generated by coupled proton/electron transfer and re–reduced by abstracting hydrogen atoms from substrate water or hydroxide–ligated to the manganese cluster. The proposed function of Y Z requires proton transfer from the tyrosine site upon oxidation. The oxidation mechanism of Y Z in an inhibited and O 2 –evolving photosystem II is discussed. Domino–deprotonation from Y Z to the bulk solution is shown to be consistent with a variety of data obtained on metal–depleted samples. Experimental data that suggest that the oxidation of Y Z in O 2 –evolving samples is coupled to proton transfer in a hydrogen–bonding network are described. Finally, a dielectric–dependent model for the proton release that is associated with the catalytic cycle of photosystem II is discussed.


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