scholarly journals Proton Translocation via Tautomerization of Asn298 During the S2–S3 State Transition in the Oxygen-Evolving Complex of Photosystem II

2019 ◽  
Vol 123 (14) ◽  
pp. 3068-3078 ◽  
Author(s):  
Maria Chrysina ◽  
Juliana Cecília de Mendonça Silva ◽  
Georgia Zahariou ◽  
Dimitrios A. Pantazis ◽  
Nikolaos Ioannidis
Keyword(s):  
Photosystem Ii ◽  
State Transition ◽  
Proton Translocation ◽  
Oxygen Evolving Complex ◽  
Oxygen Evolving

scholarly journals Water Network Dynamics Next to the Oxygen-Evolving Complex of Photosystem II

Inorganics ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 39 ◽  
Author(s):  
Krystle Reiss ◽  
Uriel Morzan ◽  
Alex Grigas ◽  
Victor Batista
Keyword(s):  
Photosystem Ii ◽  
Proton Translocation ◽  
Md Simulations ◽  
Water Channels ◽  
Catalytic Performance ◽  
Oxygen Evolving Complex ◽  
Eigenvector Centrality ◽  
Water Network ◽  
Large Channel ◽  
Oxygen Evolving

The influence of the environment on the functionality of the oxygen-evolving complex (OEC) of photosystem II has long been a subject of great interest. In particular, various water channels, which could serve as pathways for substrate water diffusion, or proton translocation, are thought to be critical to catalytic performance of the OEC. Here, we address the dynamical nature of hydrogen bonding along the water channels by performing molecular dynamics (MD) simulations of the OEC and its surrounding protein environment in the S1 and S2 states. Through the eigenvector centrality (EC) analysis, we are able to determine the characteristics of the water network and assign potential functions to the major channels, namely that the narrow and broad channels are likely candidates for proton/water transport, while the large channel may serve as a path for larger ions such as chloride and manganese thought to be essential during PSII assembly.

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.

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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