Article
Biochemistry & Molecular Biology
Brandon P. Russell, David J. Vinyard
Summary: The Mn4CaO5 oxygen-evolving complex in Photosystem II is crucial for water oxidation. D1 residue R334 participates in proton release and interacts with PsbO. A D1-R334G mutant destabilizes the OEC but stabilizes the S2 intermediate.
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
(2024)
Article
Biochemistry & Molecular Biology
Bernard Baituti, Sebusi Odisitse
Summary: The S-2 state in the oxygen-evolving complex of photosystem II produces two basic electron paramagnetic resonance signal types, with a focus on determining the spin states of the g4.1 signal at X-band frequencies. The multiline signal arises from a spin 1/2 center, while the g4.1 signal is proposed to originate from a spin 5/2 center with rhombic distortion. The experimental data support the g4.1 signal as originating from a near rhombic spin 5/2 of the S-2 state of the PSII manganese cluster.
Article
Biochemistry & Molecular Biology
Divya Kaur, Yingying Zhang, Krystle M. Reiss, Manoj Mandal, Gary W. Brudvig, Victor S. Batista, M. R. Gunner
Summary: Photosystem II uses water as the primary electron source for photosynthesis, with water-filled channels playing a crucial role in bringing in and transporting water molecules. Analysis shows that the water chain in the broad channel is better connected, facilitating proton translocation. However, the specific roles of each pathway in the oxidation and reduction processes still need further investigation.
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
(2021)
Article
Chemistry, Physical
Hiroshi Isobe, Mitsuo Shoji, Takayoshi Suzuki, Jian-Ren Shen, Kizashi Yamaguchi
Summary: In photosystem II, water is oxidized to dioxygen through a Mn4CaO5 cluster, with two competing reaction routes, stepwise and concerted, affecting the formation of the final stable closed structure.
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
(2021)
Article
Plant Sciences
Brandon P. Russell, David J. Vinyard
Summary: The study found that the first Mn2+ oxidation event in the assembly of the oxygen-evolving complex in Photosystem II requires chloride-facilitated deprotonation. This process is dependent on the presence of calcium at physiologically relevant pH values.
PHOTOSYNTHESIS RESEARCH
(2022)
Article
Biochemistry & Molecular Biology
Hiroshi Kuroda, Keisuke Kawashima, Kazuyo Ueda, Takuya Ikeda, Keisuke Saito, Ryo Ninomiya, Chisato Hida, Yuichiro Takahashi, Hiroshi Ishikita
Summary: The study utilized MD simulations and mutagenesis to identify the proton-transfer pathway in photosystem II, with D1-Asp61 being crucial in the process.
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
(2021)
Article
Multidisciplinary Sciences
Christopher J. Gisriel, Jimin Wang, Jinchan Liu, David A. Flesher, Krystle M. Reiss, Hao-Li Huang, Ke R. Yang, William H. Armstrong, M. R. Gunner, Victor S. Batista, Richard J. Debus, Gary W. Brudvig
Summary: The cryo-electron microscopy structure of PSII from Synechocystis sp. PCC 6803 has been determined at high resolution, revealing differences from thermophilic cyanobacterial PSII structures that significantly impact the understanding of PSII structure and the mechanism of water oxidation.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Biochemistry & Molecular Biology
Boris K. Semin, Lira N. Davletshina
Summary: Ca-depleted photosystem II membranes obtained by treatment with acidic buffer lack Ca2+ in the Mn4CaO5 cluster, but contain all extrinsic proteins protecting this cluster (PSII(-Ca/low pH)). Unlike native photosystem II, the Mn cluster in PSII(-Ca/low pH) samples can be reduced by small-sized reductants. By substituting Mn cation(s) with Fe cation(s) at pH 6.5, a chimeric cluster (3Mn1Fe) was obtained in PSII(-Ca/low pH) membranes containing extrinsic proteins. The resulting membranes exhibited high intensity O-2 evolution in the presence of exogenous Ca2+, reaching about 80% of the rate in PSII(-Ca/low pH) membranes.
JOURNAL OF BIOLOGICAL INORGANIC CHEMISTRY
(2023)
Article
Plant Sciences
Hiroyuki Mino
Summary: The temperature dependence of the formation of the g similar to 5 S-2 state electron paramagnetic resonance (EPR) signal in photosystem II (PSII) was investigated. It was found that the g similar to 5 signal can be produced at an illumination above 200 K, and its formation is half inhibited at approximately 215 K. The study also estimated the activation energy, enthalpy, and entropy of the g similar to 5 state formation.
PHOTOSYNTHESIS RESEARCH
(2022)
Review
Plant Sciences
Charles F. Yocum
Summary: These special issues of photosynthesis research present papers documenting progress in revealing the many aspects of photosystem 2, a unique and complex system. The author provides a personal assessment of the progress observed over a four-decade research career, discussing some remaining unsolved issues.
PHOTOSYNTHESIS RESEARCH
(2022)
Review
Chemistry, Multidisciplinary
Nataliia Vereshchuk, Marcos Gil-Sepulcre, Abolfazl Ghaderian, Jan Holub, Carolina Gimbert-Surinach, Antoni Llobet
Summary: Today, sustainable and clean energy conversion strategies rely on sunlight and water as sources of protons and electrons, similar to Photosystem II. However, the thermodynamics and complexity of the water oxidation reaction make it difficult to find efficient and stable molecules capable of achieving this task. Ru coordination complexes have been identified as some of the best understood water oxidation catalysts, and their catalytic performance and key factors influencing their performance have been extensively studied.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Chemistry, Physical
Kizashi Yamaguchi, Koichi Miyagawa, Mitsuo Shoji, Hiroshi Isobe, Takashi Kawakami
Summary: A multiple S-3 intermediates model for water oxidation in the oxygen evolving complex of photosystem II is examined based on key intermediates elucidated by calculations. The results suggest that the Mn-Hydroxide configuration plays a major role in the S3 state, while Mn-Oxyl has only a partial contribution. The oxyl-radical character is significantly reduced by the coordination of the Ca ion.
CHEMICAL PHYSICS LETTERS
(2022)
Review
Chemistry, Inorganic & Nuclear
Kizashi Yamaguchi, Mitsuo Shoji, Hiroshi Isobe, Takashi Kawakami, Koichi Miyagawa, Michihiro Suga, Fusamichi Akita, Jian-Ren Shen
Summary: This review elucidates the geometric and electronic structures of the catalytic CaMn4Ox (x = 5, 6) cluster in the water oxidation process in PSII, using high-resolution X-ray diffraction and serial femtosecond crystallography experiments, as well as theoretical computations. The interplay between experimental and theoretical methods effectively reveals the coordination structures and spin states of the cluster, and implications of these findings for artificial catalyst development are discussed.
COORDINATION CHEMISTRY REVIEWS
(2022)
Article
Plant Sciences
Keisuke Saito, Shu Nakao, Hiroshi Ishikita
Summary: The Mn4CaO5 cluster in photosystem II forms hydrogen bonds with D1-His337 and a water molecule. The hydrogen bond distances differ between the two monomer units and can be attributed to protonation and overreduction states.
FRONTIERS IN PLANT SCIENCE
(2023)
Article
Multidisciplinary Sciences
Masahiro Saito, Keisuke Saito, Hiroshi Ishikita
Summary: Despite the abundance of iron on earth, manganese serves as the catalytic center for water splitting in photosystem II. In order to understand why nature employs manganese instead of iron, a study investigated the Fe4CaO5 cluster in the PSII protein environment using a QM/MM approach. It was found that substituting manganese with iron resulted in protonation of mu-oxo bridges, highlighting the relevance of manganese in natural water splitting.