Exploring reaction pathways for the structural rearrangements of the Mn cluster induced by water binding in the S3 state of the oxygen evolving complex of photosystem II

2021 ◽  
Vol 405 ◽  
pp. 112905
Author(s):  
Hiroshi Isobe ◽  
Mitsuo Shoji ◽  
Takayoshi Suzuki ◽  
Jian-Ren Shen ◽  
Kizashi Yamaguchi
Keyword(s):  
Photosystem Ii ◽  
Reaction Pathways ◽  
Oxygen Evolving Complex ◽  
Structural Rearrangements ◽  
Water Binding ◽  
Mn Cluster ◽  
Oxygen Evolving

Reduced Derivatives of the Mn Cluster in the Oxygen-Evolving Complex of Photosystem II:  An EXAFS Study

1996 ◽  
Vol 118 (10) ◽  
pp. 2387-2399 ◽  
Author(s):  
Pamela J. Riggs-Gelasco ◽  
Rui Mei ◽  
Charles F. Yocum ◽  
James E. Penner-Hahn
Keyword(s):  
Photosystem Ii ◽  
Oxygen Evolving Complex ◽  
Exafs Study ◽  
Mn Cluster ◽  
Oxygen Evolving ◽  
Derivatives Of

Electron donation to photosystem II by diphenylcarbazide is inhibited both by the endogenous manganese complex and by exogenous manganese ions

1995 ◽  
Vol 73 (5-6) ◽  
pp. 241-245 ◽  
Author(s):  
Abdur Rashid ◽  
Radovan Popovic
Keyword(s):  
Photosystem Ii ◽  
Antagonistic Effect ◽  
Oxygen Evolving Complex ◽  
Manganese Ions ◽  
Extrinsic Polypeptides ◽  
Negative Role ◽  
Mn Cluster ◽  
Oxygen Evolving ◽  
Electron Donation

Diphenylcarbazide (DPC) is an efficient electron donor to the inactive oxygen-evolving complex of photosystem II (PSII). We investigated the role of manganese on the rate of electron donation from DPC to PSII in both Mn-depleted (Tris washed) and Mn-retaining (NaCl washed) PSII preparations. The rate of electron donation from DPC to PSII was significantly higher in Mn-depleted than in Mn-retaining preparations, indicating a negative role of native Mn complex on DPC electron donation. The apparent Km values for DPC were found to be 0.11 and 0.17 mM for Mn-depleted and Mn-retaining PSII preparations, respectively. This difference in the Km values also indicates an antagonistic effect of endogenous Mn cluster on electron donation from DPC, which was markedly inhibited by exogenous Mn2+. However, the magnitude of inhibition was greater in Mn-depleted than in Mn-retaining PSII preparations. This indicates a higher accessibility of DPC to PSII in the absence of native Mn complex. Our results suggest (i) that Mn, either endogenous or added, acts as an accessibility barrier for DPC to donate electrons to PSII and (ii) that the native Mn complex not only functions as an accumulator of oxidizing equivalents but may also protect PSII from exogenous reductants.Key words: photosystem II, extrinsic polypeptides, Mn complex, electron transport, diphenylcarbazide.

scholarly journals Thermodynamics of the S2-to-S3 state transition of the oxygen-evolving complex of photosystem II

2019 ◽  
Vol 21 (37) ◽  
pp. 20840-20848 ◽  
Author(s):  
Muhamed Amin ◽  
Divya Kaur ◽  
Ke R. Yang ◽  
Jimin Wang ◽  
Zainab Mohamed ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Photosystem Ii ◽  
State Transition ◽  
Monte Carlo Sampling ◽  
Oxygen Evolving Complex ◽  
Mn Cluster ◽  
Cluster Monte Carlo ◽  
Oxygen Evolving

The S2 to S3 transition in the OEC of PSII changes the structure of the Mn cluster. Monte Carlo sampling finds a Ca terminal water moves to form a bridge to Mn4 and the Mn1 ligand E189 can be replaced with a hydroxyl as a proton is lost.

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