Reduction-Induced Inhibition and Mn(II) Release from the Photosystem II Oxygen-Evolving Complex by Hydroquinone or NH2OH Are Consistent with a Mn(III)/Mn(III)/Mn(IV)/Mn(IV) Oxidation State for the Dark-Adapted Enzyme†

Biochemistry ◽  
2005 ◽  
Vol 44 (6) ◽  
pp. 2129-2142 ◽  
Author(s):  
Thomas Kuntzleman ◽  
Charles F. Yocum
Keyword(s):  
Photosystem Ii ◽  
Oxidation State ◽  
Oxygen Evolving Complex ◽  
Oxygen Evolving

scholarly journals Structural Changes in the Acceptor Site of Photosystem II upon Ca2+/Sr2+ Exchange in the Mn4CaO5 Cluster Site and the Possible Long-Range Interactions

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 371
Author(s):  
Koua
Keyword(s):  
Crystal Structure ◽  
Photosystem Ii ◽  
Long Range ◽  
Electron Acceptor ◽  
Structural Changes ◽  
Acceptor Site ◽  
Oxygen Evolving Complex ◽  
Long Range Interactions ◽  
Structural Perturbations ◽  
Oxygen Evolving

The Mn4CaO5 cluster site in the oxygen-evolving complex (OEC) of photosystem II (PSII) undergoes structural perturbations, such as those induced by Ca2+/Sr2+ exchanges or Ca/Mn removal. These changes have been known to induce long-range positive shifts (between +30 and +150 mV) in the redox potential of the primary quinone electron acceptor plastoquinone A (QA), which is located 40 Å from the OEC. To further investigate these effects, we reanalyzed the crystal structure of Sr-PSII resolved at 2.1 Å and compared it with the native Ca-PSII resolved at 1.9 Å. Here, we focus on the acceptor site and report the possible long-range interactions between the donor, Mn4Ca(Sr)O5 cluster, and acceptor sites.

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